You need to talk to a local expert.

I am no lending expert nor do I pretend to be one, with that said, typically conventional loans are used to fund investment properties.  

While this squatter(s) has no title, right or lease to/for the property they have been living there in the open with the knowledge of the previous owner. 

This requires more knowledge of contractors, conditions of homes, and a little more risk.

A knowledgeable, reputable mortgage banker is worth way more then the few bucks you might have saved going with the lowers rate.

We will make 80k-100k profit off the house.I'm not very knowledgeable with tax information but if we sell the house post 5/20/18, is there any reason I couldn't claim the capital gains exemption?

It might have some residual business.Becoming and expert and marketing yourself to fill your pipeline is what tends to generate leads but you still have to have the knowledge and skills to close the sale.

The more knowledge everyone has the better for the industry.

If anyone is experienced or has done the BRRR strategy in Texas your feedback and knowledge would be greatly appreciated. 

Not going to be a fun day .I am lucky to a degree , I have the skills , knowledge and equipment to tackle just about all my own repairs .