8.5” ET12 is going to be tough up front. You are going to have a lot of poke. If you roll the fenders it just might clear. My 8x17 ET20 with a 3mm spacer clears. My 235’s are so wide that it is hard to do any comparisons. Who knows about turning while cycling the suspension. You could machine the wheel flange a bit. You would be much better off trying to trade someone with an 8” square setup so they could run staggered.
My 17x8 ET20 lip clears the unrolled rear fender by about 6-7mm. An 8.5x17 ET12 wheel would be 15mm closer to the fender lip than my wheel. The fender lips themselves are about 25mm. So if you roll the rears they would fit and look pretty good IMO.
Disclaimer: The physicists may chime in with active tire load and other armchair science stuff.