Sometimes a non-conforming space also helps with the numbers if you can find one that has egress and safety standards met.

As soon a the "we found mold" card gets played, you immediately offer them to vacate with no penalty to insure their safety. 

If the original poster wants to increase equity and create safety (and keep the little woman happy) financially, then maintaining leverage (mortgages) is not necessary if title fraud is a major concern; put the paid-off properties into land trusts. 

I also really like that this is a U-shaped window unit which wraps over the window sill, meaning that you get to keep nearly all of your window's view and natural light, as well as it being theoretically harder for someone to break into the apartment by kicking in/pulling out the AC unit (ours is on the second floor, but the safety concerns for first floor units is definitely a consideration you'll want to factor in).Heating.  

I'd really tell folks to prioritize getting the location of the property and their systems in place well vetted before playing ball.

Some of the top rated schools, downtowns, neighborhood, and safety ratings in the North East.

But prioritize quality here, I'd also tell you to no more MFs & to go get a SFR.

Shouldn't we be prioritizing quality over quantity?  

Note many of your items in this project are not related to health and safety.  

Probably needs completely new electrical box and wiring for safety.