If tenants are moving out right after closing, do double check the leases clearly show the security deposit they paid the seller and you collect that amount at closing from the seller (credit to you) so you have those funds to then return to the tenants when they vacant under your ownership. 

I also haven't found any title companies in Oregon that work with wholesalers or handle double closings—unless they’re nationwide companies, which I don't know much about.

I'm not sure whether having a bedroom in the basement is good enough.

Only a reliable tenant matters.Rent range - What the segment is willing and able to pay.Configuration - Two bedrooms, three-car garage, large back yard, single-story, two stories?

Just make sure to do your due diligence, get second opinions on the rehab work, and double-check the financials to ensure it makes sense.

They also cap on rent rates based on the number of bedrooms for the tenants voucher so some of my rentals (depending on the location) will bring more rent than what Section 8 will pay .

However, I’ve noticed that larger homes (3-4 bedrooms) tend to have difficulty renting as MTRs since most MTR tenants in our area are traveling healthcare professionals, typically renting solo or with one other person.

I would also recommend double checking your pricing. 

Or a dedicated 'mini gym' corner in a spare room/basement if available.

For instance, we now charge $2800 for a 2 Bedroom Apt that used to be $1k in 1998.