Who will be saved in the Last Day?

Who will be saved in the Last Day, the Judgment Day before Christ rules over the earth?  Good question.  

Although I don't claim to get every single criteria in my answer, I will mention some of them.  I also cannot address the issue of a person's individual pre-earth life soul contract with God, in regards to mission in life and potential lifespan.  We have a veil over our premortal memories.  However, if you are seeking Divine protection in the Last Days, there are some things to remember and do.  The basic criteria for being saved, is living a righteous life, receiving the Truth, and heeding the promptings of the Holy Spirit (D&C 45:57) (taking the Holy Spirit as your Guide).

If you were an angel of God, and were looking down on humanity, who would you save?  How would you judge a person's value for the New Heavenly Kingdom on earth?  Would you judge a soul only by its heart, its spirit? How would a person be weighed in the scales?

Let's visit a story from the scriptures, in Daniel 5.   Belshazzar was a wicked king.  He loved riches (and probably was underhanded in getting them), he was not humble, he loved to party, and he greatly dishonored God.  One day, an angel wrote on the wall in his palace (only disclosing his hand to human view) a message in an unknown language.  None of his "wise" men could interpret the writing, but Daniel the Prophet could.  It was not a message that a person would want to hear.  Part of the message was, "Thou art weighed in the balances and found wanting."  The other part was that his kingdom was over and would be given over to other nations.  That was the last of Belshazzar's life.  He was slain that same night.  So, not only did he have a bad heart, but he did bad things too, particularly extra bad because his actions were destructive towards others, not just to himself.

So, it sounds like the Belshazzar passed up on opportunities to do good, and also ignored repentance until it was too late.  See Alma 35:33-35 about the perils of waiting too long to repent.
Alma 34 (churchofjesuschrist.org)

Fortunately, we in the gospel have reminders to repent, through the Sacrament ordinance, and we are supposed to examine ourselves and re-commit to live the gospel.  This regular process helps keep us from getting too far off the path.
2 Corinthians 13 (churchofjesuschrist.org)

Moroni 4 & 5 (or D&C 20:75-79) have the Sacramental prayers, if you wish to read them.

Okay, another instance where the angels were judging people at a time of judgment, is found in Ezekiel 9.  This was when Ezekiel had a vision of the wicked people of the city, and he conversed with the Lord in the vision.  There was a servant of the Lord in the vision (an angel) who marked the foreheads of the righteous.  The Lord told the servant, "..., Go through the midst of the city, through the midst of Jerusalem, and set a mark upon the foreheads of the men that sign and cry for all the abominations that be done in the midst thereof."   So you see, the righteous were marked so that they would not be hewn down in destruction.

There are other instances in the scriptures about being marked as righteous:  the Passover story in the book of Exodus comes to mind.  Before the last "plague" the faithful were instructed to mark their doorposts with an unblemished Lamb's blood.  There were other Passover instructions too.   This was so that the Destroying Angel would pass them by.

In the book of Revelation, chapter 7 (New Testament) the four angels of the Apocalypse were told by God, to mark the 144,000 who will have special tasks, "..., Hurt not the earth, neither the sea, nor the trees, till we have sealed the servants of our God in their foreheads."  [See also D&C 77:9]

So, in the Passover, it was a physical marking on the doorposts, identifying their homes that they had entered into a covenant with the Lord, and that they had His promise of protection by doing what He said.

In Ezekiel 9 and Revelation 7, it was undoubtedly, a spiritual marking, imperceptible to the natural eye, but seen by God and his angels. 

Zion will be a great protection to its inhabitants.  Read D&C 97.

Here's an excerpt:

21 Therefore, verily, thus saith the Lord, let Zion rejoice, for this is ^aZion—the pure in heart; therefore, let Zion rejoice, while all the wicked shall mourn.  

22 For behold, and lo, vengeance cometh speedily upon the ungodly as the whirlwind; and who shall escape it?  

23 The Lord’s scourge shall pass over by night and by day, and the report thereof shall vex all people; yea, it shall not be stayed until the Lord come;  

24 For the indignation of the Lord is kindled against their abominations and all their wicked works.  

25 Nevertheless, Zion shall escape if she observe to do all things whatsoever I have commanded her.  

26 But if she observe not to do whatsoever I have commanded her, I will visit her according to all her works, with sore affliction, with pestilence, with plague, with sword, with vengeance, with devouring fire.

The Mark of the Beast, will be a physical sign but with devastating physical and spiritual effects, because they will experience the Wrath of God.  The Mark is in contrast with being sealed by God's angels, or by putting a Godly sign on one's house.   I am personally against Halloween, and it's interesting to note the correlation that in this ghoulish holiday, tricks or treats are dispensed at the doorposts of one's home.

Revelation 13

15 And he had power to give life unto the image of the beast, that the image of the beast should both speak, and cause that as many as would not worship the image of the beast should be killed.

16 And he causeth all, both small and great, rich and poor, free and bond, to receive a mark in their right hand, or in their foreheads:

17 And that no man might buy or sell, save he that had the mark, or the name of the beast, or the number of his name.

18 Here is wisdom. Let him that hath understanding count the number of the beast: for it is the number of a man; and his number is Six hundred threescore and six.

Revelation 16

2 And the first went, and poured out his vial upon the earth; and there fell a ^anoisome and grievous sore upon the men which had the mark of the beast, and upon them which worshipped his image.

9 And men were scorched with great heat, and ^ablasphemed the name of God, which hath power over these plagues: and they repented not to give him glory.

10 And the fifth angel poured out his vial upon the seat of the beast; and his kingdom was full of ^adarkness; and they gnawed their tongues for pain,

11 And blasphemed the God of heaven because of their ^apains and their sores, and repented not of their deeds.

So you see, in theory it would be hoped that those who take the Mark of the Beast, repent, but the record says that they don't repent.  This implies that the prophet John (writer of Revelation) hoped they would repent, but they won't or don't.

Be a Wise Virgin (Matthew 25).

There is a lot here to ponder about from these scriptures.