First property, generally freaking out

[Justin Dziedzic]

Ok. I acquired my first property about 5 months ago. Purchased from my aunt who was a heavy smoker so I knew there would be some rehab. I had scrubbed most walls with TSP (not all) and primed with 1 coat of kilz. Tenant has been in for about 5 weeks now and there have already been a variety of issues including what looks like nicotine or another old stain seeping through the paint (see pics). A few painters have said they've seen this, especially with heavily smoked in homes and to reprimer and paint. My worry is that some spots have a powdery middle spot to them, not all. Visible in one pic.

My big concern is mold. I don’t think this is mold but it got me thinking about mold. The basement is typical damp feeling. I added damprid buckets and will be getting a dehumidifier but anything else I can do to be aware of? 

I’m not sure my anxiety can handle being a landlord. Inspection occurred about 4 months ago and no signs of anything troublesome.