What about turnover costs (when a tenant leaves, you'll likely have to paint, replace some flooring, repair or replace cabinets/countertops, etc)?

My exit strategy is to leave these properties to my daughters twins 8 years old and a 7 year old.

You don't even have to leave the state to see shenanigans like this.

I realize verbal agreements mean nothing, but it did leave us feeling very positive that we would get the signed contract.

I was Googling to see about FNMA delayed financing on primary properties in Texas (Texas has stringent primary property equity loan guidelines) and saw this post on investment properties.FWIW - we provide FNMA delayed financing for investment properties regularly, and what you are leaving on the table in terms of lost leverage as it is being discussed here seems to be incorrect.  

How do you lock in a deal while leaving an out?

I would not leave Texas out of any investment discussion for so many reasons.

...Seems most of your other questions have already been addressed, leaving the one being quoted here.

It's Gated, fancy marble flooring, it leaves guests breathless...

this looks like a very good deal if vacancy is more around 10%.. rents would be 14400 at the lower end of the spectrum, which leaves you with theoretical 3400 per month. which is 35% CoC off the top of my head.