Both handicapped people and little children are examples of the compassion and love that humans have towards those who suffer in this lifetimes. In fact, we should feel that same compassion and hope towards all humans, whether they are suffering or not, that they would get to paradise. But the reason why we tend to especially focus this hope on examples such as helpless children and handicapped people is because we also have a deep sense of justice alongside our gifts of love and compassion. We desperately want these people to go to heaven because in our opinion it would compensate for the unfairness of suffering in this world or dying prematurely.
Love, compassion, justice - what amazing gifts we have and what amazing creatures we humans are!!!
Personally, I do not think we can draw sweeping conclusions concerning the fate of any category of persons as a whole. Each person is an individual with their own personal relationship with God. Each person is also a sinner by nature even before they commit their first sin. Jesus is the only person who is totally sin-free. Even babies are sinners by nature although not yet by deed. we can compare babies with, say, lion cubs. Even though a lion cub is cute and cuddly and hasn't killed any prey itself, it is still a wild animal and a predator - it is what it is even before it has grown into being one. Humans are the same.
But this is not a problem for us because God deliberately made us this way. He does NOT expect us to be perfect before accepting us, he expects to believe in him and his mercy and to love him for it.
Young children trust in their parents with complete blind faith and that is what God wants from all of us. This surely does not mean that only those who are intellectually capable of studying bible, meditating on such matters as righteousness, sanctification and justification can get to be with God! Why? Because God has placed his law into our hearts, it is no longer written externally on slabs of stone. It is our conscience that read and knows that law intuitively.
Therefore God's love and mercy extends to all those that during their lives have followed their conscience and shown love towards their fellow humans. Paul talks about this is Romans (Ch 2:14).
Naturally, the issue of belief in Christ arises in these situations because the bible talks about faith in Christ and not just "kind-hearted atheists". But we cannot judge what other peoples' faith is about. Many people do not go to church or talk about their beliefs, but this does not mean that deep inside it is not there. Nor do we know what happens inside in those last moments as someone dies. Equally, we do not know if those who most vividly express their faith are actually genuine in their belief!!
I am sure we all know people whom we love who have died without any clear indication of faith in Christ and about whose fate we worry. I personally take encouragement from Paul's letter 1 Cor 3:10-15. This suggests that even the smallest mustard seed of faith will keep us saved even if only by our fingertips:
"If it is burned up [what we have built on Christ's foundation] he will suffer loss; he himself will be saved, but only as one escaping through the flames."
The bottom line? Well, we cannot really answer the question whether particular individuals go to heaven because it is God's decision, but if love and compassion are God's gifts to us and people have shown a willingness to use these gifts during their lifetimes, is God going to abandon them entirely in spite of all the prayers from their family and friends still on earth? I doubt that. Therefore, I think we have good cause to be positively hopeful and trust in God that love and justice will indeed prevail for all people, especially for those whose own opportunities to walk with God on this earth were limited in scope or duration.