There is probably an easy yes or no answer to this, but I can't find it anywhere online or in my Nolo books: if I have repair costs "incurred" prior to me putting a rental into service, but were actually paid with cash after the rental was put into service, do I still capitalize them along with the purchase price and then depreciate? 

I am seeing that people have one large policy that can cover a portfolio and simplify things, would be great to find a broker or company with experience that could set something like that up.

I suspect though banks did not chase too much of it in the melt down prior 

When I was listing and selling property full time, I always advised the seller to get estimates and negotiate a credit to the buyer;  it avoids so much stress, lost time, etc.Of course it is not always possible, depending on the repair--the lender may refuse to close prior to a certain repair being made.But whenever possible, I'd recommend  to credit the buyer and let them deal with it. 

However, the big hurdle has been that most lenders that we have spoken with want to see the retail component of the project at least 50% leased prior to commitment.

I had insurance policy that covered the loss of rent and the HOA cut us a check to renovate it ourselves.

you need to assess if the seller has any money and do you want to spend thousands chasing them for years even if your right and have the right to sue.. or just pony up the money and pay for the fix.. although home inspection should have got something that was glaringly bad and of course you should have read the docs prior to closing that you got from HOA... 

I bought a 3/2 single family in 2016 and converted it to a 4/2 prior to renting it in 2017.

In many cases just getting an umbrella policy is cheaper and easier to do if liability protection is your goal.

I kind of lucked out comparatively speaking, but f you’re at the attorney stage (which it sounds like you already were prior to writing this post) it pays to shop around for the next steps.