Questions about Judaism?

Shalom. I’m a soon-to-be ex-Catholic with a few questions about Judaism, and was wondering if someone could help me with them. (Just to be clear, my intention is not to offend in any way; I’m only asking out of genuine curiosity.) So without further ado, here they are:

• According to Judaism, do all righteous people go to heaven regardless of their faith?

• Why does God want you to guess who the Messiah is?

• What’s your most difficult responsibility as a Jew (according to yourself)?

• What are the most important rules (if you can’t follow them all)?

• What happens to people who leave Judaism (respectfully, for their personal reasons)?

• What distinguishes the several branches of Judaism (and do all of them encourage circumcision)?

• Christianism teaches us that we’re born “unworthy” of God’s grace and that pretty much everything we do is wrong, very wrong… Is Judaism like that, too? What place does self-esteem have?

• Is there a distinction between how “bad” people’s sins are, or are all sins considered equal and punishable by “hell”?

• Are you allowed to ask honest questions and have doubts, or is that considered daring/shameful/judgmental?

Thanks in advance!