Engine kits--eBay (I assume you are referring to gasket/ring sets, Manny).
Caster--I do not mess with it much, but the TCA(s) can be shimmed a bit (or deshimmed) to play with caster where they attach to the stabilizer bar.
I use an older style Ground Control camber plate kit for camber, but in Production, you can check out adjustable TCA(s) that are available in the UK (Demon Tweeks) for the "foreign" Escorts. The new style GC plates have an adjustment for caster as well ans camber.
A trip to the frame shop and some "strategic tugging" on the strut towers (inward) can also get you some more camber.
I source my struts in the UK. You can go with either a LEDA or an AVO in a real coil-over, but you may need to shim the receiver in the knuckle to accept the struts. BAT used to sell such adaptor pieces, but I had a buddy machine a pair for me--real simple--for my GP car which uses the same knuckles as are on your GT.
My ITC car is an early model(1981), which has knuckles identical to what was sold on these cars in Europe. You have Tempo-derived knuckles and hubs. Yours are beefier and use a press-in cartridge bearing. The old style use regreasable tappered bearings which can be disassembled in the field.
If you can snag a Ford special tool kit for the suspension, do it. The Hub remover/installer is a good tool and the proper way to disassemble the hubs.
Cheers.