I try post again
Your 1st and 4th question covered by my longer rely to DB9T and Mogga.
Hatred between and within religion owing to misunderstanding, deviation
Search will show small/big sins in Islam, God forgive all except one, providing you ask for forgiveness and change your ways, if no change then repentance not accepted.
But it's like an earthquake, the trembling still carries on for a while after the earthquake stops - some sinning ways take longer to correct than others to be able to live by God's laws.
