There is some additional information that wasn't mentioned in your post above which sheds a different light on the situation.  1.

Citizen Borrower Eligibility Requirements, for additional information.

Give her 30 days notice now, keep her security deposit, and send her a additional bill for damages to the unit in lieu of taking her to court for the damages.  

Electric: is the easiest to split, but may require holes cut in walls to separate the units.Gas: gas lines aren't as flexible as wires, but it can usually be done affordably.Water: most cities will NOT install additional water meters on a property.

If things work out, we'd like to have at least 1 additional property before the end of the year and have 8 in 8 years.

In addition, due to them being eligible for conventional non-commercial financing they typically have lower cap rate than 5 units and more.  

What do you mean you are paying $400 additional dollars more than what you are paying now?

Additionally, it's a good idea to connect with a Property Manager early on.

That could be achieved without spending an inordinate additional amount in cap ex; In fact all I have seen had these items in common1.

Additionally, most servicers will provide the tax documents needed at end of year (1099-INT, 1098-INT) and can also issue notices of NSF, late payments and support delinquency /default.