Category 1: the basement shows some hairline cracks at the frost line; and some stair step cracks but no heaving, and only minor evidence of moisture..Question: what type of repairs should I plan for?

Interesting...it almost looks to be sagging, but that is usually caused by moisture or a structural issue...but there is no apparent water damage...It could be faulty material or the contractor didn't use the correct installation process...the other consideration would be climate...expansion and contraction that causes the drywall/mud to crack over time...IF it is sagging, there needs to be some more investigation...the contractor will drop the ceiling back to the next rafter and poke around to find the cause...that is an open-ended repair...you can get a cost for the investigation, but no the repair.A final thought would be that if it's just cracking and there is no sag, install crown molding... 

She stated the first year she has a renter she schedules quarterly visits to change out filters, and check under sinks for leaks or moisture problems, and check smoke detectors, ect..  

I mean, mold all over the walls with moisture damage, and it appears that the tenants are hoarders.

You're looking for possible repairs whether expensed (like dumpy apts needing rehab on a turn) or CapEx (roof has <5 years, siding has moisture invasion, leaky plumbing, paving is starting to break up). 

Also, check to make sure there are no leaks in the roof or any moisture getting into the home due to siding or roof issues. 

Moisture intrusion is the worst enemy in housing....

Probably could be done 2 coats in a day and would reduce moisture intrusion by 95% even if done by an amateur.

You can put the moisture barrier in for very minimal expense.

What caused it in the first place needs to be resolved and that is moisture.