You will be fine... I ran a 12.5 on a 7" wide wheel and I'm currently running 14" wide Iroks on an 8" wide wheel. It may wear a bit faster in the center, but I doubt you will notice. The good thing is a narrow wheel acts as a "poor mans beadlock" as it's a lot harder to loose a bead at lower tire pressure while wheeling.
3.5" lift will swamp 34's. If you add spacers to increase lift, they will look tiny.
I will eventually run 37's on my F.O.R. Gen II kit (I took my rig on washboard this week, you can hardly feel it, I cannot believe how good this thing rides. On 35" MT's my rig is competing with my luxo minivan for ride quality).
OME medium max height if you want 34's to look good. At 4" you are going to start wanting 37's, trust me.
I am currently running the 35" Trxus with NO lift. I do not get any rubbing until I start to flex... Then I do get rubbing. I am waiting on my F.O.R. Gen II lift kit. I can't wait until I get them!!! Come on Frankie... ship the damn things.... .
Back to the Trxus, I have had Toyo M/T's on a Chevy Blazer and now I have had the Trxus on my FZJ80. So far I absolutely LOVE the Trxus. They are quiet and friggin awesome in the snow!!!