|Gustave Dore's depiction of the highest realm of Heaven,|
from Dante's The Divine Comedy.
Yes, that's true. As you love in this life, your capacity for love increases, as does your capacity to receive the glory and blessedness of heaven. So, whereas Saint A and Saint B are both filled completely and thus have no notion of being slighted or being without, if Saint A acted with greater charity in this life then he will be filled with more joy because he has the capacity to receive more. To use your analogy, Saint A and Saint B both have buckets filled to the brim, but Saint A's bucket is larger.
Scripture is clear about there being levels or degrees of honor in heaven. See, for example:
- Mt 5:19 Whoever then relaxes one of the least of these commandments and teaches men so, shall be called least in the kingdom of heaven; but he who does them and teaches them shall be called great in the kingdom of heaven.
- Mt 11:11 Truly, I say to you, among those born of women there has risen no one greater than John the Baptist; yet he who is least in the kingdom of heaven is greater than he.
- Mt 18:4 Whoever humbles himself like this child is the greatest in the kingdom of heaven.
For more on this, see my blog post, "Levels of Honor in Heaven and Mary's Queenship."
If so, does this also apply to Christ who we will be united to? Does it matter to him in heaven if we led saintly lives on earth, or lived as Sodom but had a deathbed conversion? Similarly, does it matter to Christ in heaven if every baby is aborted with no life experience (or, let's say every one year old is killed) vs them living a meaningful life?
I'm sure that it matters to Jesus a great deal. While it is true that a person who has a deathbed conversion can wind up in heaven right alongside the person who lived a lifetime of holiness, it does not follow that how those two people lived their lives is incidental to God. There is no guarantee that the person living a life of sin will even have the opportunity to make a last-minute appeal to God, nor that he will seize the opportunity if he is given it. God desires that we choose holiness now, and not just for our own sake, but for the sake of the Church and the whole world.
Yes, the good thief repented at the end and was able to be with God, but think of the good he could have done for himself and for others if he had repented sooner! Think of the glory he might have given to God ... and the glory he might have stored up for himself in heaven! Yes, his bucket is full in heaven, but it could have been a much larger bucket. God wants to fill us up with as much of His life and His love as we can possibly be filled up with.
We will (all) be united to Christ in heaven -- does that in some way mean to each other also?
Yes. Just as it is for the Church on earth, so will it be for the Church in heaven: Our unity to the Head of the Body also establishes our unity with one another. As Scripture says:
- Rom 12:4-5 For as in one body we have many members, and all the members do not have the same function, 5 so we, though many, are one body in Christ, and individually members one of another.
- Eph 1:9-10 For he has made known to us in all wisdom and insight the mystery of his will, according to his purpose which he set forth in Christ 10 as a plan for the fulness of time, to unite all things in him, things in heaven and things on earth.
- Eph 2:19-21 So then you are no longer strangers and sojourners, but you are fellow citizens with the saints and members of the household of God, 20 built upon the foundation of the apostles and prophets, Christ Jesus himself being the cornerstone, 21 in whom the whole structure is joined together and grows into a holy temple in the Lord;
- Eph 4:15-16,25 Rather, speaking the truth in love, we are to grow up in every way into him who is the head, into Christ, 16 from whom the whole body, joined and knit together by every joint with which it is supplied, when each part is working properly, makes bodily growth and upbuilds itself in love. 25 Therefore, putting away falsehood, let every one speak the truth with his neighbor, for we are members one of another.
- Col 2:18-19 Let no one disqualify you, insisting on self-abasement and worship of angels, taking his stand on visions, puffed up without reason by his sensuous mind, 19 and not holding fast to the Head, from whom the whole body, nourished and knit together through its joints and ligaments, grows with a growth that is from God.
If true, is my experience of heaven lessened by those with lessor lives (or no lives, aborted, etc.)? If false, is my experience of heaven no different because of others --- so why should I care if in the end they don't matter to me?
I don't think it follows from the communion of the saints in heaven that their experience of heaven would be lessened by the presence of members who did not live greater lives of charity. Your experience of heaven depends on the size of your bucket, and only you can determine that.
Also, regardless of the lives that the other saints led and how they got to be with you in heaven, your bucket is completely full. You can't get any happier than you are at that moment. You are beholding the beatific vision, the unmediated presence of God. You want for nothing.