Who is Elias?

Is Elias a title, office, calling, spirit, power, mission, ordinance, code name, specific person, or all of these depending on the image and intent in the mind of a speaker or writer¹? Since there seems to be various theories of who Elias is, here are several references from the JST (JST amendments are bolded; red highlights the name Elias):

12 And from the days of John the Baptist until now the kingdom of heaven suffereth violence, and the violent take it by force.
13 But the day will come, when the violent shall have no power; for all the prophets and the law prophesied that it should be thus until John.
14 Yea, as many as have prophesied have foretold of these days.
15 14 And if ye will receive it, verily, this is he was the Elias, which who was for to come and prepare all things.
16 15 He that hath ears to hear, let him hear.
Lutes, Kenneth and Lyndell. Joseph Smith Translation (p. 2136). Lutes Publishing. Kindle Edition. (JST New Testament | Matthew 11:12-16)

9 10 And his disciples asked him, saying, Why then say the scribes that Elias must first come?
10 11 And Jesus answered and said unto them, Elias truly shall first come, and restore all things, as the prophets have written.
11 12 But And again I say unto you that Elias is has come already, concerning whom it is written, Behold, I will send my messenger, and he shall prepare the way before me; and they knew him not, but and have done unto him, whatsoever they listed.
12 Likewise shall also the Son of Man suffer of them.
13 But I say unto you, Who is Elias? Behold, this is Elias, whom I sent to prepare the way before me.
14 13 Then the disciples understood that he spake unto them of John the Baptist, and also of another who should come and restore all things, as it is written by the prophets.
Ibid.-Lutes, (p. 2153). (JST New Testament | Matthew 17:9-14)

9 11 And they asked him, saying, Why say the scribes that Elias must first come?
10 12 And he answered and told them, saying, Elias verily cometh first, and restoreth prepareth all things; and teacheth you of the prophets; and how it is written of the Son of Man, that he must suffer many things, and be set at naught.
11 13 But Again I say unto you, That Elias is indeed come, and but they have done unto him whatsoever they listed; and even as it is written of him; and he bore record of me, and they received him not. Verily this was Elias.
Ibid.-Lutes, (p. 2218). (JST New Testament | Mark 9:9-11)

13 But the angel said unto him, Fear not, Zacharias: for thy prayer is heard; and thy wife Elisabeth shall bear thee a son, and thou shalt call his name John.
14 And Thou shalt have joy and gladness, and many shall rejoice at his birth;
15 For he shall be great in the sight of the Lord, and shall drink neither wine nor strong drink; and he shall be filled with the Holy Ghost, even from his mother’s womb.
16 And many of the children of Israel shall he turn to the Lord their God.
17 And he shall go before him the Lord in the spirit and power of Elias, to turn the hearts of the fathers to the children, and the disobedient to the wisdom of the just, to make ready a people prepared for the Lord.
Ibid.-Lutes, (pp. 2250-2251). (JST New Testament | Luke 1:13-17)

25 But I tell you of a the truth, many widows were in Israel in the days of Elias, when the heaven was shut up three years and six months, when and great famine was throughout all the land;
26 But unto none of them was Elias sent, save unto Sarepta, a city of Sidon, unto a woman that who was a widow.
27 And many lepers were in Israel, in the time of Eliseus the prophet; and none of them was were cleansed, saving save Naaman the Syrian.
Ibid.-Lutes, (p. 2264). (JST New Testament | Luke 4:25-26)

18 And it came to pass, as he was went alone praying with his disciples were with him to pray, and he asked them, saying, Whom Who say the people that I am?
19 They answering said, Some say, John the Baptist; but some others say, Elias; and others say, that one of the old prophets is risen again. ...
54 And when his disciples, James and John, saw this that they would not receive him, they said, Lord, wilt thou that we command fire to come down from heaven and consume them, even as Elias did?
Ibid.-Lutes, (p. 2282, 2284). (JST New Testament | Luke 9:18-19, 54)

20 19 And this is the record of John [the Baptist], when the Jews sent priests and Levites from Jerusalem to ask him, Who art thou?
21 20 And he confessed, and denied not that he was Elias; but confessed, saying; I am not the Christ.
22 21 And they asked him, What then saying; How art thou then Elias? And he saith said, I am not that Elias who was to restore all things. And they asked him, saying, Art thou that prophet? And he answered, No.
23 22 Then said they unto him, Who art thou? that we may give an answer to them that sent us. What sayest thou of thyself?
24 23 He said, I am the voice of one crying in the wilderness, Make straight the way of the Lord, as said the prophet Esaias.
25 24 And they which who were sent were of the Pharisees.
26 25 And they asked him, and said unto him, Why baptizest thou then, if thou be not that the Christ, nor Elias who was to restore all things, neither that prophet?
27 26 John answered them, saying, I baptize with water: but there standeth one among you, whom ye know not;
28 27 He it is of whom I bear record. He is the prophet, even Elias, who, coming after me, is preferred before me, whose shoe’s latchet I am not worthy to unloose, or whose place I am not able to fill; for he shall baptize, not only with water, but with fire, and with the Holy Ghost.
Ibid,-Lutes, (p. 2337). (JST New Testament | John 1:20-28)

2 God hath not cast away his people which he foreknew. Wot Know ye not what the scripture saith of Elias? how he maketh intercession complaint to God against Israel, saying,
3 Lord, they have killed thy prophets, and digged down thine altars; and I am left alone, and they seek my life.
4 But what saith the answer of God unto him? I have reserved to myself seven thousand men, who have not bowed the knee to the image of Baal.
Ibid.-Lutes, (p. 2499). (JST New Testament | Romans 11:2-4)

17 Elias was a man subject to like passions as we are, and he prayed earnestly that it might not rain: and it rained not on the earth by the space of three years and six months.
18 And he prayed again, and the heaven gave rain, and the earth brought forth her fruit.
(New Testament | James 5:17-18; no changes in JST; compare Luke 4:25; Old Testament | 1 Kings 17 & 18)

5 Behold, this is wisdom in me; wherefore, marvel not, for the hour cometh that I will drink of the fruit of the vine with you on the earth, and with Moroni, whom I have sent unto you to reveal the Book of Mormon, containing the fulness of my everlasting gospel, to whom I have committed the keys of the record of the stick of Ephraim;
6 And also with Elias, to whom I have committed the keys of bringing to pass the restoration of all things spoken by the mouth of all the holy prophets since the world began, concerning the last days;
7 And also John the son of Zacharias, which Zacharias he (Elias) visited and gave promise that he should have a son, and his name should be John, and he should be filled with the spirit of Elias;
8 Which John I have sent unto you, my servants, Joseph Smith, Jun., and Oliver Cowdery, to ordain you unto the first priesthood which you have received, that you might be called and ordained even as Aaron;
9 And also Elijah, unto whom I have committed the keys of the power of turning the hearts of the fathers to the children, and the hearts of the children to the fathers, that the whole earth may not be smitten with a curse; (Doctrine and Covenants | Section 27:5-9)

9 Q. What are we to understand by the angel ascending from the east, Revelation 7th chapter and 2nd verse?
A. We are to understand that the angel ascending from the east is he to whom is given the seal of the living God over the twelve tribes of Israel; wherefore, he crieth unto the four angels having the everlasting gospel, saying: Hurt not the earth, neither the sea, nor the trees, till we have sealed the servants of our God in their foreheads. And, if you will receive it, this is Elias which was to come to gather together the tribes of Israel and restore all things. (Doctrine and Covenants | Section 77:9)

14 Q. What are we to understand by the little book which was eaten by John, as mentioned in the 10th chapter of Revelation?
A. We are to understand that it was a mission, and an ordinance, for him to gather the tribes of Israel; behold, this is Elias, who, as it is written, must come and restore all things.
(Doctrine and Covenants | Section 77:14)

11 After this vision closed, the heavens were again opened unto us; and Moses appeared before us, and committed unto us the keys of the gathering of Israel from the four parts of the earth, and the leading of the ten tribes from the land of the north.
12 After this, Elias appeared, and committed the dispensation of the gospel of Abraham, saying that in us and our seed all generations after us should be blessed.
13 After this vision had closed, another great and glorious vision burst upon us; for Elijah the prophet, who was taken to heaven without tasting death, stood before us, and said:
14 Behold, the time has fully come, which was spoken of by the mouth of Malachi—testifying that he [Elijah] should be sent, before the great and dreadful day of the Lord come—
15 To turn the hearts of the fathers to the children, and the children to the fathers, lest the whole earth be smitten with a curse— (Doctrine and Covenants | Section 110:11 - 15)

45 Elias, who was with Moses on the Mount of Transfiguration;
46 And Malachi, the prophet who testified of the coming of Elijah—of whom also Moroni spake to the Prophet Joseph Smith, declaring that he should come before the ushering in of the great and dreadful day of the Lord—were also there.
47 The Prophet Elijah was to plant in the hearts of the children the promises made to their fathers,
48 Foreshadowing the great work to be done in the temples of the Lord in the dispensation of the fulness of times, for the redemption of the dead, and the sealing of the children to their parents, lest the whole earth be smitten with a curse and utterly wasted at his coming. (Doctrine and Covenants | Section 138:45 - 48)

As we can perhaps observe from these scriptures, Elias can be applied to John the Baptist, Elijah, John the Revelator, Gabriel, one who is to restore all things, and even Christ himself (see JST New Testament | John 1:20-28 above).

------------------------------/
1. https://dejavu-timestwo.blogspot.com/2014/02/here-and-there.html
https://dejavu-timestwo.blogspot.com/2015/02/words-without-images.html