Are the type 1 irs and early type 2 irs (3 rib 002) input shafts the same?

Depends on how "the same" your after. As actual parts they are different, but to use as a clutch alignment tool they are the same, ie. as far as fitting the engine is concerned they are the same, but they vary inside the gearbox.

So I had a mishaps whilst trying to undo the rear right hub but to put studs in the rear of the bug... I read that it's ok to drive forwards with a breaker bar on the nut. Bad move. So I'm guessing the point of fail was the inputs shaft as the rear wheels still affect each other , the transaxle still goes into gear but won't take any power from the engine. So I know it's engine and trans out now. If the input shaft is a goner then is it straight forward to replace without special tools? I've got some good circlip pliers...

Doubt very much you've broken the input shaft. First guess and easiest to fix would be clutch drive plate, but more info re noises and feel to help any further. So to answer og question, no, they are different I believe, and not easy to change on the type 1 box.
Stock input shaft can handle like 800+hp

omfg I frickin hope it's just the drive plate. No weird sounds I reved the engine up but as I engaged each gear felt nothing and saw nothing in the wheels. No clattering of gears or nothing when I spun the wheels in gear so I can't be right up shit creek.

Kinda sucks when u try and do the right thing by putting studs in the rear therefore making car safe for future owner but Murphy won't let you do it straight and simple every time I guess. I'll pull the motor tomorrow and see if I'm up for a new plate.

What was the diagnosis mate?