Here's the service manuals..
http://werbatfik.com/Capri_Service_Manual.htmAs for the rest, sounds a little like a Capri that needs a lot of work. Ok, yes the engine is Mazda, was in the 323, even a turbo version 2 or 3 years before the Capri was launched. Many other parts are Mazda as well.
You asked a lot of questions and mention a number of problems, wish I could address them all, but this would go on too long. Russ Carlson at Roo-Sport.com is our best friend as Capri owners. However, getting ahold of him can be challenging at times. If he does not respond to phone messages try finding his eBay store and messaging him through the site messaging. Another site is ModernCapriParts.com who seems to have a lot of hard to find parts. They know that, as proof, just examine their pricing.
If looking for OEM parts, those are the two most promising sources. If you know an exact part number, try asking at a Ford or Mazda parts counter, but even my local dealer which had a good reputation for parts has become a one answer machine if I call and ask for a part by year, make and model. Parts others report getting are denied me by telling me "they are no longer available" or "I don't show those in my books". I'm learning to ask for a particular part by number.
If you need aftermarket parts, or parts store parts (replacement), RockAuto.com is king, and FlyinMiata.com has a number of great performance upgrades. I just got my ARP head studs and Comedic head gasket from them.
Good junkyards are key, I have one by my office that has 7 Capris in various stages of decay. AFAIK, new windshields are all gone, but nice used ones can be had. Another option is to buy a parts car. I paid $300 for a non running dented 94 N/A which has provided me thousands of dollars in parts if I had to buy them individually. My pick was unusually good, but I've seen a lot of Capris, running or not, for $2000 very nice ones, $1000 drivable, and under $700 tow-aways.
Your interior, I'd see if you can get a decent parts car and swap the pieces in. Almost every original seat out there is torn, the original foam crumbles. A lot of us fabricate brackets and swap in nice junkyard seats, I have BMW 318i heated seats in mine.
I've overstayed my reply again... There's a lot of work in that car. We'll try to help with answers.