Also look behind the kitchen sink, Dishwasher, and Fridge, from that then get a mold assessor ( expensive ) or a regular home inspector that can do air samples. 

Does anyone have any recs for buying kitchen cabinets?

Updated the kitchen, repainted the house, and replaced the roof, as well as cleaning up the landscaping.What was the outcome?

I redid the entire house (drywall, HVAC, roof, landscaping, kitchen, bathrooms, and surfaces).

We plan to take out a wall and add an island to open the kitchen up, take the carpet out of the bathrooms (yes, really), replace most of the flooring, finish the 4th bedroom and the rest of the basement, and various other minor updates.

When I signed my tenants into a year long lease, we made an agreement (addendum on the lease) that they would pay for new carpet and kitchen flooring out of their pocket in exchange for a lower monthly rent.

I also renovated the bathrooms and one of the kitchens. 

The rest could go towards remodeling the bathroom(s), kitchen, and paint. 

We plan to take out a wall and add an island to open the kitchen up, take the carpet out of the bathrooms, replace most of the flooring, finish the 4th bedroom and the rest of the basement, and various other minor updates.

We completely remodeled the kitchen and rest of the house but think we will leave the bathroom alone for now since it’s not within budget to renovate.