Is it his force ghost or actually him?

Actually him, by the time of Episode III

Yes

He defeated two Sith Lords, both with and without the high ground. Not to mention he mopped the floor with General Grievous and Jango Fett, both highly accomplished warriors, known for killing Jedi.

Yes I would like it if he we

No. If I had my choice I'd prefer qui gon jinn

I rather have Ashoka