OR do I have to get 2 separate loans?

Lets look at each separately...For your renovation work, you can't really "just split the profits." 

Property A, B, C: Do we have to file three separate partnership returns or can we just file individually?

Property A, B, C: Do we have to file three separate partnership returns or can we just file individually?

In addition, the money for the repairs will either need to come from your pocket or a separate line of credit if available (assuming you are financing the deal). 

This was paid off several times & the last guy put in a $15k kitchen, complete with granite counter tops, all new hardwood flooring, some appliances & due to his business failing, separation/divorce & just giving up we took it back & paid the current tax arrears of $4k.There will be many opportunities & cash will be the deciding factor, in fact this week we agreed to HML/finance a foreclosure for a fellow investor. 3 rental properties on 16 acres for the asking price of $59k, CASH.

If I was the landlord in this scenario, I would handle it similar to how your landlord did....file for eviction and sue you for past due rent.Granted the son doesn’t sound like a great guy, but he also lives in a completely separate single family house from you.

You'll probably need signatures from both of you on separate documentation for both properties.

Is it as simple as writing a check directly into her self-directed IRA or must there be a designated, separate spousal IRA?

That is a separate a\mount and typically I see 3% commission fee to a realtor