Hi mate,
I believe that the cut out only is on the series 4afe engines the where made for the 95, I can tell you that a 20v does not have the relief in the block for the transfer case! However you can grind it back if you want. ( I have done this ) the lump in the floor you speak of is for the cat / muffler on the exhuast . Did /have you measured the tunnel demensions as I thought they were different?
The rear you could use a strut type spring/damper combination, over the 5 link solid axle set up, still would be a lot of work though! , what state are you in? Can this be engineered?
This of course assumes there is enough clearance for everything?
Good luck if you proceed. I have a shell and diff ect...... If you want it.