I've been looking into sub-metering a SFH home with a mother-in-law suite and experiencing difficulties regarding zoning and the utilities companies.

I also lend money but not in the USA at rates which in the USA would be considered userous but in other places are quite common and quite legal as well.  

That's a very common practice.

I feel like I’m very blessed and lucky to be in my current situation and that I could be better utilizing my financial situation to build real wealth instead of clawing away at it annually via W2 wage income only (and saving only ~$70k/year).Unfortunately when I model out deals, with today’s cap rate environment, I can’t find anything that generates meaningful levered free cash flow.

Terms are important, lot rent amounts are important, utility expenses, tax, etc.

Personally, I have utilized VA and conventional loans over FHA, but you can run your numbers with different loan scenarios and choose what is best for you.

Are there any others out there who have utilized SFR buy and hold strategy in Texas that would be willing to share their story - pros cons etc.?

Too utilize the maximum value I would make this in to a single 4-5 bedroom house.

That’s ARV, , number of bedrooms, rents, expenses (including any utilities), conditions and estimated repairs costs, etc ...Why?  

There are many different formats but most have some things in common.