Info you seek is out there i suggest you try harder, i found it alright when i did mine, although sometimes the info was very scattered across forums.
Problems:
As you know the oil sendor in normal AE86 is a pressure sendor where as the digi uses a switch type as only a warning light comes on when oil pressure is too low. AE92 oil sendor will work.
Fuel sendor you need is from a early 90's Soarer/chaser digi dash model for cheapness or go genuine its your call. pretty sure you need 1 extra wire for it too work properly.
This is off the top of my head from my digi dash along time ago so info maybe alittle off.
Plugs are the same although the wires dont line up properly. Handbrake/park light ends up being the exhaust gas temp light i think. There is a conversion chart somewhere, ill see if i still got mine. Oh and the check engine light will come on if you dont run a speed sensor which i never had luck figuring out. Aftermarket ecu solved that problem.
Benefits:
None for me anymore, its wank value but each too their own i guess.
Honestly not worth the hassle unless your dead set on the fact its a different and somewhat cool cluster id either sell it or bin it and save yourself the hassle.