Engine swap noob. Procedures, cautions and tips

It's been long overdue, but this winter it's finally time for the engine swap I've been planning a couple of years now. I have a 92 cabby with the "2H"-engine that has steadily been loosing oil pressure and now it's close to zero even when cold. Earlier this year I tried to change the oil pump to no avail. But since I've had the offer of getting a 92 Vento for free as a donor vehicle, the plan has always been to engine swap the cabby if no easy fix could be found.This is regarding a swap between two digifant units, the old one a 1.8 litre speced to 98hp and the other a 2.0 litre (stroker) with 116 hp. The swap should be straight forward as engine mounts are concerned, The oil pressure in the donor is excellent with around 5-6 bars in the head and after a couple of heat cycles it quieted down and purred like a kitten. So that's promising.

So now I have the donor in my garage, ready to yank the engine out from it. My plan this far is to do a complete overhaul once it's out. Headgasket, timing belt, clutch kit, cleaning and so on, but his is were I need your help. I recon these particular engines are quite uncommon in the UK, but with the collective knowledge here I might still have loads of useful help.

So what to look for upon teardown? Wich of the two ECUs to use? I've read somewere that the head of the 1,8-engine is better suited for this application. But I can't remeber were or why.

What kind of light tuning mods could be done? I'm thinking mild cam and perhaps a header of sorts? What can you really expect performance wise without swapping the stock ECU?

I'm sure there will be more questions, but I'll start off with these. Cheers from gloomy sweden!