I feel the PM contracts are too weak re motivating a PM to select problem free tenants so you would be well served setting the standards for tenants.

@Evan HamamotoZillow is def junk, weak eviction check and paystub forgery is real.

With that said  we have done several flips together and know our strengths and weaknesses.  

In addition, I have a willing guarantor who owns $400mm+ in MF property.The issue I'm worried about is that some mortgage brokers I've spoken with, and Michael Reinhard's book on commercial mortgages, say that I need to have 3 years of proven income (I changed jobs a bunch after college) as well as good credit (don't have) and previous ownership experience (don't have) in order to get a loan.On the other hand, when I read things from some other sources like the BP forums, or from investors like Dave Lindahl, they state that with a strong guarantor a bank will still give me a loan to buy a property even if I have weak credit, insufficient net worth or lack of experience.I'm looking at some deals and I would be looking to borrow 65-70% LTV, non-recourse and 10yr fixed and all of the deals I'm looking at have a 1.6+ DSCR. 

There are plenty of ways to operate ethically and legally with poor credit, if you are weak in one area, you need to be stronger in another area to make up for that weakness.

Everything in my life has changed over the last five years due to the diagnosis and treatment of a chronic illness.

You will have a chance to talk to people who have various strategies and you can start to figure out what will fit your strengths and minimize your weaknesses.

Again, that is so weak an excuse I'd run it past the TX REA and prove me wrong since I'm in OR. 

If the borrower is weak on paper but states they can pay the mortgage, is this OK because of the seller not having to prove the ability to pay?

While obviously much more forgiving than any other material when frozen the weak point then becomes the fixtures themselves, or, in the case of anything with hot water baseboard, the baseboards are always still copper and will split quickly once they freeze.