Huge demand, and a shrinking supply due to condo conversions means you have an extremely high probability of your property value going up significantly over time.

If you don't trust the person inquiring about your rental and their motives decline them.

As @Jay Hinrichs mentioned foundation issues are extremely common in Texas. 

That is extremely useful.

The solo 401k allows for checkbook control from the onset; The solo 401k allows for personal loan known as a solo 401k loan; It is prohibited to borrow from your IRA; The Solo 401k may be invested in life insurance; The self-directed IRA may not be invested in life insurance; The solo 401k allow for high contribution amounts (for 2018, the solo 401k contribution limit is $55,000, whereas the self-directed IRA contribution limit is $5,500); The solo 401k business owner can serve as trustee of the solo 401k; The self-directed IRA participant/owner may not serve as trustee or custodian of her IRA; instead, a trust company or bank institution is required; When distributions commence from the solo 401k a mandatory 20% of federal taxes must be withheld from each distribution and submitted electronically to the IRS by the 15th of the month following the date of each distribution; Rollovers and/or transfers from IRAs or qualified plans (e.g., former employer 401k) to a solo 401k are not reported on Form 5498, but rather on Form 5500-EZ, but only if the air market value of the solo 401k exceeds $250K as of the end of the plan year (generally 12/31); When funds are rolled over or transferred from an IRA or 401k to a self-directed IRA, the amount deposited into the self-directed IRA is reported on Form 5498 by the receiving self-directed IRA custodian by May of the year following the rollover/transfer.

You probably don't need a lawyer on a small deal like this, provided you have a good, trusting relationship with your father-in-law and you don't want to do this through a business entity (like an LLC).

When we were looking 2 years ago, buying was an option, but the market is too hot right now for us to afford.It's a challenge locating a promising place while not local to the property, and that's why I'm turning to a trusted resource - BiggerPockets!

Earlier this year I acquired my first duplex, and I'm extremely excited for what lies ahead. 

While Texas is a non-disclosure state, the appraisal districts are pretty good about capturing values off deeds of trust, etc so expect that number to be higher after the sale unless you bring a lot of cash to the table. 

If you do not have MLS access, I would speak to a trusted real estate agent and see what the DOM and price /Sq Ft is for similar homes in that area.