Probably no psionics, and tieflings are fine.
Also, I'm alright with evil characters provided there's a good reason to not cause a huge conflict. A character who serves a Demon Lord, though, would tend to cause problems with the party's divine casters, which is why the warlock from my campaign before would not have been a good choice.
We probably won't be using Maptools as I don't know what that is.
ETA: I'm not sure I'm the right person for this job, as running a game electronically is something I have literally no experience with.