Using the listing agent as your agent has the advantage of the listing agent wanting to get biggest commissions - so your offer might get preferential treatment (if very close to what others have offered).

How is their treatment of retirement income attracting retirees?

It's hard to prove, but I suspect that offers made directly with the REO listing agents often get preferential treatment.

He is going to fly into the US to have treatment and wants to use this foreclosure to keep his mind off of cancer while he receives treatment.

My last one (3 bdrm, 1 bath, 2 car SF house) ran me about 16k for everything (i.e. new flooring, drywall repair, scraping popcorn ceilings off and re-texturing, new ceiling fan, new fridge, landscaping, all new interior & exterior paint, some new electrical, foundation repair, termite treatment, complete gut & remodel of bathroom, two new doors and all new door hardware through the house, new water heater, etc etc etc).

A principal residence does not qualify for 1031 tax treatment.Even if you convert the property to a rehab-flip, you still don't qualify for 1031 tax treatment.

I took a personal loan of $100K at 5% and lend it for my LLC to purchase a rental. I plan to charge my LLC 6% interest rate.1. Is there any benefit to write up the loan as a mortgage vs a regular business loan?2. When...

He feels the need to do quarterly rodent treatments to the tune of $500 up front, then $125/quarter

A lot of their lower-priced properties are good for rental plays and a lot of the higher-priced properties out of my reach (finance and experience wise), that's not to mention the prefered treatment their accredited investors get. 

Occupational Therapists often have a treatment plan which involves therapy animals, and I would have very little doubt that the courts and regulating agencies would side against a landlord on reasonable accommodation based on an OT not specifically being mentioned in the guidance memo.