Do the Apparitions of the Virgin Mary  have any bearing on the Second Coming of Our Lord Jesus Christ? Is there any direct Biblical and historical support to expect all these apparitions?
The best way to seek for the answers to these questions is to prayerfully consult the Holy Scriptures.
A formula is proposed regarding the steps leading to the Second Coming of Our Lord Jesus Christ which contains two elements that are tied to each other in a very intimate way:
The return of the prophet Elias
A. The return of the prophet Elias
Note: Many thought that John the Baptist was the prophet Elias, the one who according to the prophecy of Malachias (4:5) was to come back to the world. He was indeed Elias and Our Lord testified to that fact [see above], however, he was not the only Elias manifestation which Malachias spoke about.
"Behold I [God the Father] will send you Elias the prophet, before the coming of the great and dreadful day of the Lord". [Mal. 4: 5]
Note: God the Father was certainly not talking about the birth
Our Lord when He said: "...the great
and dreadful day of the Lord."
This is a clear reference to the Second Coming since on His First Coming, it was not a "dreadful day". Yet, Elias, manifested through John the Baptist was also to come before the First Coming without contradicting that it also applied to before the "...dreadful day of the Lord." and he did. The question may still remain about how far "before" the Parusia was Elias to return again. Our Lord may have answered that question through St. Matthew.
Note: Jesus does not deny that Elias is to come first for He confirms that the mission of John the Baptist is that of Elias. He then makes a point of noting that His messianic mission will be rejected with violence, and then Elias will have to return to "restore all things" [presumably at the "end of times"] as the precursor of His final triumph. Yet, how soon before the Parusia?
The third and last manifestation of Elias is finally confirmed by St. John in the Book of Revelations under the guise of one of the: "two witnesses", "two olive trees", "two candlesticks" [Rev. 11:3-5]. This "twosome" is considered by some scholars to be Enoch and Elias [according to Scriptures (Eccl. 44:16, 48:9-10 and 49:16), they never died]. By others, the "twosome" is considered to be Moses and Elias.
We also see references about that mighty "twosome" in Zacharias 4:1-14. Elias is the common figure in either illuminated opinion. Therefore, we cannot speak of the return of the prophet Elias without acknowledging the prophecy of the "two witnesses", and vice-versa.
"Let no man deceive you by any means, because the apostasy will come first, and the man of sin be revealed, the son of perdition, the adversary, the one who relishes in whatever is of God or holy, until finally sitting himself in the temple of God, conducting himself as if he were God."  [2Thes. 2: 3,4]
saw another beast coming up out of the earth, and he had
two horns, like a lamb, and he spoke as a dragon". and "And it
was given him to give life to the image of the beast, and that the
image of the beast should speak; and should cause, that whosoever will
not adore the image of the beast, should be slain". [Rev.
13: 11; 15]
C. The Parousia
It must be noted that these "tribes" are all the nations of the earth as opposed to the "tribes of Israel".
A SIMPLE ANALYSIS
Studying the proposed two step formula a few very salient points emerge.
From those readings, it appears very clearly that "Elias" is more than just one single specific human being. "Elias" was represented by John the Baptist and Jesus also clearly stated that "Elias" will be back to "restore all things" while God, the Father, through Malachias, had already informed us of the same.
It is also acknowledged in traditional theological circles that when it is said: "The Law and the Prophets" it symbolizes "Enoch and Elias" or "Moses and Elias". That is, "Elias" appears to be the equivalent of "Prophets".
Now, since "Elias" is to come again toward the "end of these times", and it is solidly established that John the Baptist was that "Elias" announcing the first coming of the Lord, we may conclude that this time, for the Second Coming, "Elias" may take a different form.
It is proposed that the new manifestation of Elias is announced, by inference, by the Virgin Mary, specifically, through Her apparitions at Medjugorje which started on the day the Church celebrates the birth day of John the Baptist.
Mary is proclaimed by the Roman Catholic Church as the Queen of Prophets, thus, it is within Her God granted prerogative to announce the manifestation of any of Her subjects.
Malachias [3:1] prophesies: "Behold I send my angel, and he shall prepare the way before my face. And presently the Lord, whom you seek, and the angel of the testament, whom you desire, shall come to his temple. Behold he cometh, saith the Lord of Hosts".
Keeping in mind that "angel" means "messenger", it is also befitting that the Virgin Mary, who is also considered Queen of Angels by the Roman Catholic Church, be the appropriate messenger spoken about by Malachias.
This message is further underscored by Jesus Himself in Matthew 11:10 "For this is he of who it is written: Behold I send my angel (messenger) before thy face, who shall prepare thy way before thee." as He makes references to John the Baptist in previous verses.
Thus, it is certainly fitting for Jesus to announce the manifestation of Elias for the First Coming and for Mary to announce it for the Second Coming. In a marvelous and mysterious way The Prophets and The Angels were bound mystically in the Queen of Prophets and Angels, The Ever Holy and Virgin Mary.
"And I, John who have heard and seen these things. And after I had heard and seen, I fell down to adore before the feet of the angel, who shewed me these things. And he said to me: See thou do it not: for I am thy fellow servant, and of them that keep the words of the prophecy of this book. Adore God. And he saith to me: Seal not [seal = hide, obscure, put away] the words of the prophecy of this book: for the time is at hand". 
Fellow servant? The Virgin Mary, the Queen of Heaven and Earth? Yes, indeed! She Herself made that pronouncement: "Behold the handmaid of the Lord;..." [Lk. 1:38] and then proceeded in haste to visit and serve Her cousin Elizabeth as a humble handmaid. To fully comprehend this concept/parallelism we must call to mind Our Lord’s words and example as He washed the feet of the Apostles.
WERE MARIAN APPARITIONS FOR THE END TIMES FORECASTED?
The concrete Biblical evidence announcing Marian Apparitions toward the End of These Times should be clear to those who have Eyes to see and Ears to hear. Not only that, we are encouraged through Rev. 22:10 to "proclaim the information / instructions being given to us" and not to hide it [seal it].
We may then agree that Marian Apparitions were announced and well documented as far back as in the times of Malachias. Our Lady has said in the apparitions of the second half of the 20th century that those will be Her last messages and apparitions on earth. This concurs with all other Marian and Christian manifestations on earth . It should then follow that the stage for the Marian Apparitions in the 19th and 20th Centuries was set over 2,000 years ago and that we are at the gates of the End of These Times.
It appears, then, that the proposed formula is a reality. Therefore, it can be safely concluded that we should be already be seeing the manifestations of the forces of the Anti Christ/False Christ and that, finally, Our Lord will be coming again amidst Power and Glory.
 If the reader does not believe
in the Apparitions of the Virgin
Mary, for the sake of establishing internal coherence, assume them to
be a reality while reviewing this document.
 Translated to English from Dr. Straubinger’s Translation [into Spanish] because it is the only true rendition of2Thessalonias 2:3,4 ever encountered.
 "Two horns" presumably refers to the Episcopal miter.
 "...time is at hand." is not when St. John lived. It is the point in time he was witnessing, by a Special Grace and reporting on. This time frame is made clear in verse 6 of Chapter 22 of the Book of Revelations.
 Key Marian Manifestations
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The Parousia... But When?