So progress came to a complete halt because I keep either running into rust that has seized stuff together, or I'm missing parts.
Fortunately (as of last night) I think I've finally sourced the last parts I need. Picked up a set of new-ish K Sport coilovers and E30 axles from a guy parting out his ti locally. Same guy I bought the e28 diff from, never occurred to me initially to see if he had the axle setup.
K Sports have 0 miles on them as he bolted them to his ti that was undergoing a swap, but somehow the top rubber bushing got torn. I'm going to get a hold of K Sport today and see what we can do about that. But it was too good a deal to pass on this suspension. Axles are also brand new, so it worked out well.