Having to this made me cringe a little, the original strategy on the project was to BRRRR, but due to some hidden costs that popped up, renting it out no longer looked like a solid return.

On table 19 (page 38) I see that one of their biggest expense was "Premium and fees on redemption of MTN".

Your lack of firmness over time may have lulled this tenant into putting less priority on paying his housing bills.Some tenants are chronically late and pay the rent by mid month, plus the late fees.

Any recommendations for banks with low fees/complicated setups (setting up a Wells business bank account was basically hell) etc?

The attorney's fee would be worth it.

I believe he had a sub 10% fee at the time as well.  

Don't sink money into an attorney unless you see specific value they can provide.I think all in if you're $250 in fees/costs to pursue, with possibility even of only say 20% of repayment, at the $10,000 - I'd take those odds every time.

Some have recommended a short-term rehab loan, but I would like to avoid this as I have the cash for repairs and want to avoid paying the higher interest rate and fees associated with that type of loan.  

For example for my sister in law we charge a 10 percent monthly fee for a 4plex, no leaseup fees even though the renter gets charged a 200 admin fee so we are making 360 a month.

They like to say their rates are better than hard money but by the time they are done with all their fees it’s about the same.