The number above on the rehab might be reasonable but maybe not so if you are close on numbers then don't forget you are protected in your "option period" with a standard Texas REC contract.  

Normally as @Craig Yarnell said you finance one way to purchase the property and then after a period of "Seasoning" you refinance to get most or all of your money out. 

During the pre foreclosure period, what do I do or what documents do I need to lock in the property?

Your 1031 Exchange fails if you are not able to acquire any of the properties that you identified during your 45 calendar day identification period and you would pay the capital gain and depreciation recapture taxes that would have paid as if it was a regular sale. 

I want to refinance asap after rehab but I've heard that the house won't appraise to its full ARV if refinanced within the seasoning period of 6 months and that you've to wait out entire seasoning period to appraise to full ARV.

I HIGHLY recommend one with a thermal imaging scan to detect moisture collection behind walls and roofs.  

Good morning BP,I was reading this article Felipe Mejia posted about BRRRR for beginners, and it said this about the seasoning period. 

Depreciation is simply spreading out a business expense over a period of time.

The owner may be motivated to sell during the redemption period.

https://thedarwiniandoctor.com...Essentially, because my avg rental periods are less than 7 days, and because I do spend lots of time managing my own short term rental, I am eligible to have my airbnb income/losses go against my W2 that I receive from my full time job.