No rubber gas lines, no rubber gaskets in gas tank, i.e. gas cap, petc0ck seal, etc. I think with the petc0ck conversion and nitrile gaskets you'd be ok there.
Inside the carb, I'm not familiar enough with the make up, but any rubber/softer oil based product will have to go, which there may not be any.
With such a conversion, you'd be perfectly safe running 10.5-11:1 compression. You could boost compression and cooling effect even more by running straight ethanol (and lower cost fuel, about 80% is fine.) With no timing/compression mods your fuel economy will suffer, but 2 points extra compression would bring that back, however you'd be unable to run pump gasoline if you optimized for ethanol.
One main change that would need to be made in the carb is much richer jetting. You need approximately 10-15% richer jetting, but Lancer's carb tuning steps would dial you in perfectly. If your currently running a 150 main, I'd suggest starting with a 165 and tune from there. Although maybe a 160 would work fine with E85.
I tried to be comprehensive here, but actual changes may be significantly less involved. You'd probably be ok just changing out the fuel line and re-jetting. As other gaskets dissolve over time, they could be replaced...
Hope this helps.