Plus any miscellaneous payments such as interest, inspections, etc.

  - Always do a sewer scope during inspection.  90% of the "major" expenses Ive seen that surprise new buyers are sewer related.   

Don’t skip a professional inspection of the property, as there could be hidden issues such as structural damage or code violations.

I gave her some runway to get her finances in order and although she can be a bit of a squeaky wheel, she pays on time for the past 2 months.As the person is still paying, I would just stay on them about the late payments, collect the late fees and inspect the property to be sure they're not damaging the inside.

Have a candid conversation about how he plans to handle representing both sides and ensure you’re protected with things like a solid inspection period and contingencies.

I had the house inspected when I bought it, and nothing really came to light about this. 

There are several companies I know locally who recommend replacing every single line that they scope, whether it needs it or not and I won’t let them near my properties or any of my clients properties that are being inspected by buyers.

If you don't, the next seller (ie the person buying your flip) will have an inspection done and then ask for $ to cover a new septic. 

Especially so when taking over from another company mid-lease (do you do inspections of all units before taking over).

Just make sure you to have an inspection period to review things more.