When someone expresses interest in applying, I let them know if there's already an application (or more) on the rental and that it's a first come, first served basis.

If every unit is the exact same size and layout my original assumption is that each unit should be rented out relatively the same.

I think most investors put them in an LLC, but it may not make sense based on the size of the deals, etc. 

We lived in 20-year-old, beaten down, rat-infested trailers with two to a room and nothing but a bunk bed, twin size mattress as old as the trailer, and a metal wall locker.

High velocity could work but you need the correct ductwork size (installed by someone with HV experience).

It will be tough to qualify without a lot income to show but it will depend on the loan size (you might not be able to do FHA 3.5% but you can put more down to lower the loan amount and improve your DTI).

Checkout Taylors Window and Screen near Cherrydale as they custom make the sizes you need.

That may require modifying the opening size, but that may be faster or cheaper than waiting for custom windows.

We are running into financing issues with our bank because there’s no slab & it’s not anchored, in addition to the original size being unknown.

Seriously though, VA loan has served me very well with my personal homes and my investment career.