Well nothing else in the 35. I would plan on getting something a little larger, such as a 125. Triggers need a lot of swimming room and will not be very happy in a 4 foot or less tank and may harass other fish because of cramping.
Definitely nothing in the 35 though. What I would suggest is that you get a 65, keep the trigger in there by itself and turn the 35 into a mini reef so that you can have the best of both worlds.
Many people will tell you that they have an undulated with this and that, but what they won't tell you is when it starts unleashing its anger one day and begins killing everything.