1) Yes at the beginning of my run, not after a few points spent in the skill
2) I don't know I've dedicated 1 character to this with stealth/sleazy hand
3) I think you can't steal some items if its not high enough but it's rapidly not a problem with 5 or 6 points invested
4) I do have a specialist for this, It makes some quests easier but it can mess up some dialogues if you steal the npc before talking to him
5) dont know