No, an LT95 is not an LT85 and never will be, LT stands for Leyland Transmission, the 77/85/95/230 number refers to the distance between shafts in millimetres-and hence the LT85 is weaker than an LT95, with the LT77 as the weakest of the lot. An LT95 with tapered roller bearings is still an LT95, if anything refer to it as an LT95a. An LT95 has the gearbox and transfer in one integral case and is a four speed+dual range, the LT85 uses the LT230 transfer case separate to the LT85 gearbox case, and is a five speed+the LT230's dual range. Different bellhousing, gearbox mounts, everything.
Yes the frames/chassis are galvanised on Perenties. Not sure about material thickness but some seem to think so. Might just be the 6x6s.
The 6x6 wheelbase is 119.7" primary and 155" overall, so theoretically could just squeeze a 35" tyre in, 255/85/16s would be perfect