Irrelevant facts prove nothing. Fact: a "little flock" exists. Fact: "144,000 come out of the Great Tribulation"; Fact: "Every eye will see Christ's return (Rev. 1:7); Fact: Christ's coming will be as visible as a lightning storm flashing from east to west (Matt. 24:27 NKJ)
What do these facts prove? Nothing, there is nothing connecting them that leads to a conclusion.
But if there is a logical connection, then a conclusion can be made. Christ's return won't be seen by "spiritual eyes only", because it will be as visible as a lightening storm flashing in the sky:
"For as the lightning comes from the east and flashes to the west, so also will the coming of the Son of Man be. (Matt. 24:27 NKJ)
Behold, He is coming with clouds, and every eye will see Him, even they who pierced Him. And all the tribes of the earth will mourn because of Him. Even so, Amen. (Rev. 1:7 NKJ)
As for the proposition only two groups are saved, that is clearly wrong:
We see that in the Sheep and Goat parable. Christ's brethren, already saved were seated with Him during this judgment. He points to them when talking to the sheep and goats. After this judgment, the rest of the earth's population that survived Armageddon enter Christ's 1,000 year kingdom, to see if they will be saved also:
31 "When the Son of Man comes in His glory, and all the holy angels with Him, then He will sit on the throne of His glory.
32 "All the nations will be gathered before Him, and He will separate them one from another, as a shepherd divides his sheep from the goats.
33 "And He will set the sheep on His right hand, but the goats on the left.
34 "Then the King will say to those on His right hand,`Come, you blessed of My Father, inherit the kingdom prepared for you from the foundation of the world:
35 `for I was hungry and you gave Me food; I was thirsty and you gave Me drink; I was a stranger and you took Me in;
36 `I was naked and you clothed Me; I was sick and you visited Me; I was in prison and you came to Me.'
37 "Then the righteous will answer Him, saying,`Lord, when did we see You hungry and feed You, or thirsty and give You drink?
38 `When did we see You a stranger and take You in, or naked and clothe You?
39 `Or when did we see You sick, or in prison, and come to You?'
40 "And the King will answer and say to them,`Assuredly, I say to you, inasmuch as you did it to one of the least of these My brethren, you did it to Me.'
41 "Then He will also say to those on the left hand,`Depart from Me, you cursed, into the everlasting fire prepared for the devil and his angels:
42 `for I was hungry and you gave Me no food; I was thirsty and you gave Me no drink;
43 `I was a stranger and you did not take Me in, naked and you did not clothe Me, sick and in prison and you did not visit Me.'
44 "Then they also will answer Him, saying,`Lord, when did we see You hungry or thirsty or a stranger or naked or sick or in prison, and did not minister to You?'
45 "Then He will answer them, saying,`Assuredly, I say to you, inasmuch as you did not do it to one of the least of these, you did not do it to Me.'
46 "And these will go away into everlasting punishment, but the righteous into eternal life." (Matt. 25:31-46 NKJ)
That was a judgment of Christendom, those who didn't commit to Christ before He landed on earth. Only the sheep enter, the goats are cast away.
But then the rest of the earth's population must be judged, all who survived Armageddon. Those who didn't commit eternal sins are permitted to enter Christ's millennial kingdom, to be tested once again by Satan at the end of the 1,000 years:
7 Now when the thousand years have expired, Satan will be released from his prison
8 and will go out to deceive the nations which are in the four corners of the earth, Gog and Magog, to gather them together to battle, whose number is as the sand of the sea.
9 They went up on the breadth of the earth and surrounded the camp of the saints and the beloved city. And fire came down from God out of heaven and devoured them. (Rev. 20:7-9 NKJ)
To the above groups, more are added. Death and Hell release their dead and some of them are written into the book of life:
11 Then I saw a great white throne and Him who sat on it, from whose face the earth and the heaven fled away. And there was found no place for them.
12 And I saw the dead, small and great, standing before God, and books were opened. And another book was opened, which is the Book of Life. And the dead were judged according to their works, by the things which were written in the books.
13 The sea gave up the dead who were in it, and Death and Hades delivered up the dead who were in them. And they were judged, each one according to his works.
14 Then Death and Hades were cast into the lake of fire. This is the second death.
15 And anyone not found written in the Book of Life was cast into the lake of fire. (Rev. 20:11-15 NKJ)