I bet you and I have lived and played in similar neighborhoods.I am an active investor and always in search of good properties. 

I run all expenses through the LLC bank acct, you bet.  

Typical sizing for an a/c system is one ton per 600 sf of living area.  

Done right, this can get you economy of scale and some favorable pricing (i.e. less than what you'd paid to roof a single family home of comparable size).The down side can be things like agency costs, poor management, and financial mis-steps.The bottom line: what are you getting for the dues?

Their family is growing in size and they will likely need a larger unit in the next year regardless  of current events.I want to act reasonably and to cover all the bases.

I'll bet you'd consider that :-)I agree, but I exhaust ALL options to locate decent deals.  

In the beginning, my goal was like 6 properties in 6 years, then the more I read it grew to 28 properties in 6 years...now I've got my eyes set on mid-sized apartment complexes in the future.

I would bet a vacation rental would do well.

Dont forget to factor your rehab when putting together an offer. if you're serious, get a contractor to give you an estimate on the rehab so you can better understand what its going to take to bring this property up to your standards. finding a distressed property and using the 203k is probably your best bet to make these rules work in your favor. 

There are two more bedrooms down there with closets and egress windows (one of the egress window is not quite to code size so it's not legally a bedroom) and a full bath (needs major work though - never finished).