http://db.gamefaqs.com/console/xbox/..._influence.txt
This link will give you everything you need to know on how to influence your party members. I followed the guide and managed to gain the maximum amount of influence with every party member, including HK-47. It should help you figure out where to go and what to do to get HK talking. There aren't many spots I recall off-hand, but if you work it right you can have all your possible-Jedi as Jedi and learn from HK's experience.
I don't know everything he says offhand, but his stories are semi-interesting. He even mentions people like Atton.