LS400 90-95 rear diff compatibility

Hi all would though would post this here, it is bit of a mod question and doing research. am in the frantic web search stage or looking at the feasibility of making a mid engine 4wd buggy with IFS IRS. hence turning the 1uzfe and gb around and tranfer case at the front and flipping the LS diffs so they are reverse high pinion.
1st question i guess is if drill new drain plug on top (bottom) and drill new diff breather i can fill the diff nearly to the top with oil to keep the bearings oiled? and everything is ok?
2nd is the crown wheel and pinion the same size as hilux mk1-3 solid axle ones? e.g. 8" crown wheel and the pinion the same size. as then can get a 5.29 yukon crown wheel and pinion? or are there other C+P ratios that fit the lexus diff?