One item you didn't mention was light fixtures and plumbing fixture upgrades.

Full Doc light Doc and no Doc with low DCR (1%)

How confident are you that you could order the right plumbing or lighting fixtures that match the hardware you've got in the walls?   

However; with it being built and assembled on the lot, I'm sure it will probably still be considered manufactured housing, which by the way is a cost efficient way to build and in many instances more energy efficient. 

Splash & Dash (paint and light repairs)?  

Was there any talk of making this a 'green' project (zero energy), or anything along those lines?

If you do, certainly don't make the fan come on every time someone turns on a light to wash hands or brush teeth.

I don't know much about wrap-around mortgages (though if others were to shed some light I would definitely read those comments), but if this were me in the situation, I would offer the seller a "subject-to" deal. 

The complex also backs to the new light rail station that just started running. 

I need to change vanity, faucets, toilet itself, tile the floor, paint and install lights.