Suicide is actually a grey area, biblically speaking. If the mother was not a Believer, then yes, she would go to hell. That would be no different if she died of Natural Causes. If she was a believer I can say that God has the final Judgement.
In the case of the Rapist and murderer of a Child, Also a hard one to think about. Leave it up to God I guess. Jesus Forgave a Murder while on the cross and told him he would be in Paradise with him that day. So, yeah, It can be done. However, it was an honest repentance from the murderer, Not a Cheap attempt at fire insurance. If you believe that a murder is always a murderer then I would assume that you also think that trying to rehabilitate inmates is pointless. Let's just shoot em all and let God sort them out.
Is hit going to turn into a "Can God Create a Boulder bigger then he can lift" kind of thing. Oh dear God in Heaven, I hope not.
The problem with thinking like this is it puts God in a Box. He created the friggin Universe, do you really expect him to be understood by his creation fully?