Depending on his involvement other than providing the cash you need and it will probably effect his profit split to do the deal. 

Then apply a mill rate, reduced to an effective mill rate, which is multiplied to assessed value.

I got a message from one of them saying that they need to get out of the lease asap - their partner has a temper and has caused damage to the unit, the tenant also sent photos of a hole in the wall, damaged door and trim, and something thrown in the kitchen staining the kitchen cabinets. 

The Houston ones would hopefully give me:a. positive cashflowb. enough equity that a 10% market correction would not effect me (if and when that happens)My primary residence was bought in 2011 at the low as a short sale with some robo signing agreement so I did not pay any closing costs.

if not properly vented, it can cause your shingles to prematurely break down or melt, as well a build up moisture which can lead to damage on the actual roof sheeting.

My thought is that if there is a lease in effect, the new owner would not be able to raise the rent until the lease ends.

You'll want to be sure that you know what their damage is before buying because when they come to do the inspection, the owner frequently has to make the repairs.

I've seen a tenant calculate how much damage to the house she should cause because she was positive that she wasn't going to get her deposit back.  

My gut tells me to send her a letter next month explaining the situation and propose a $200/month rent increase effective Jan 1st, 2019.

If you don’t learn from it, that is the mistake.First off, you should likely keep that security deposit if the damage to the house warrants.