Young Catholic,
With regard to infants who have died going to heaven, I would direct you to II Samuel 12,when David's infant son born out of his adulterous relationship to Bathsheba dies, In vs. 23 David being God's elect says "I shall go to him,(where?)but he will not return to me." I think this clearly states(at least in this case) that an infant that dies will be in heaven. Quite possibly all infants who die are indeed God's elect.
In regard to scripture being corrupted by men in translation. I pose this question, is not the Sovereign God of all the universe able to preserve His word against such corruption? The answer to that is a resounding YES.