I had already decided when their lease was up they were getting a hefty increase, which encouraged her to move on after a few months of M2M.  

When is their lease expiring?

Generally what I see is Hubby is handyman and Wife does books and leasing..

These are a couple of things we do during our lease audit process.This is a prime example of why investors need reserve funds.

Of course if you are required to pay off the 2% mortgage then your cash on cash ROI goes way down, but with a 30% equity cushion you’re still way ahead.I really dislike contractor for deed, lease option, or not recording warranty deed as “solutions” for the due on sale clause.  

The reason being they did not want to be caught in a lease and have to deal with potential lease issues down the road.

I have a C-Corp (no assets) as the Prop Manager  to manage leasing and rental collection for all 4 LTRs.

You didn't say anything about whether the lease or local laws actaully allow you to do this. 

I would suggest leasing a commercial space for your business first before you go straight to purchasing a space.

We have a clause in our lease that plumbing clogs not caused by mechanical/material defects in the plumbing will be charged to the tenant, and if your lease doesn't have similar I would recommend such a clause.