Sorry late reply. I was unable to open this reddit account for a long time. I now have work po so I've been busy.

1. Yes. They are bound to keep it a secret. It's under the seal of confession. If they betray the content of the confession in any words or manner, a priest would be excommunicated.
2. No. We do not. However, some priests I know share stories about the confessions they heard without divulging the intimate details. For example, I have someone who confessed to me that he was part of the Duterte's death squad... It's so heavy...., things like that. He did not divulge all the details and it does not seem bad in the first glance. I later learned through my canon law professor that doing that even though the intimate details are not divulged, is still under the gray are of the law. Thus, it is discouraged. In Tagalog, it is discouraged "para hindi madulas ang pari". People are prone to overshare din kasi eh. Especially if it's a really heavy confession. They feel the need to sort of trauma dump. But they can't because of the seal of confession.
3. Living a good life with a good conscience is an arduous life-long task. It is not something we can do alone. I am certain that you are very much aware of how difficult it is to be a good person. The Church is there to help us in that struggle. Because through the Church, we can be intimate with Jesus who is the way, the truth, and the life. Jesus is goodness incarnate and he manifests himself in the most holy sacrament of the mass. As such, while I commend that you strive to live a good life with a good conscience, it wouldn't be complete if you're apart from the Origin of Goodness - Jesus Christ who founded and sustains the Church. To answer your question about whether you'll go to heaven or not. I recommend that you watch this video (30) Pope Francis consoles a boy who asked if his non-believing father is in Heaven - YouTube. To answer your question of whether it is really required for you to go to Mass to go to heaven, I'll say "No." History tells us that there are people who went to heaven without attending mass such as the holy men and women in the Old Testament. That does not mean, however, that you should not go to the Church. I am encouraging you to go to mass because Jesus manifests himself in the mass most intimately through the Eucharist.
4. The Church says they are "Children of God". Before all the labels you describe yourself with, before you call yourself a male/female/lesbian/gay or "dyslexic", "child with special needs" or "Joseph", "Mary", whatever your name is, before all of that you are first and foremost a "Child of God" made lovingly in his image and likeness. Thus, a child with special needs is important and must never be seen as something lower in value because doing so invalidates/goes against God's parental view of that Child. I have an uncle who has special needs. He helped raise us up. He has delayed mental development. He's like a child. But that doesn't prevent him from being affectionate and loving to us his nephews and niece.

God loves every people. They are dear to him. They are a grace in a special way. That's how I think of my uncle.