Your decision to lease this property for short periods is what makes this a short term rental property, not the property itself.

I know this will be a trial and error for myself but if it was easy everyone would be doing it right.

We have made money buying properety based on cash flow (lower priced) rented out for a period, then selling to an owner occupant. 

For the 10 year period spanning December 2014-2024, single-family prices in Austin nearly doubled, yielding an annualized appreciation rate of ~9.4% in that period.With inflation close to its 2% target and an uptick in the labor market, The Federal Reserve may be taking a break from rate cuts.

How do you think the 2 relatives will feel about having their rent raised or being required to pay rent period?

Typically, you can only do one rollover per 12-month period (again, IRS Publication 969 has the details).In the end, having the option to invest your HSA funds is usually a better bet than letting them sit in a basic savings account.

They then missed out on several more years of growth because they got out of the game and waited on the sidelines for things to look better. 2010 to 2012 was the period that cash investors were the players or those with IRA keep in mind investor loans were still basically non existent in those years for all those expect very well to do Investors beginners were not getting investor loans. 

Would you share 3 specific things I should do during my "training period" (if it includes a book, which one)?

This isn't 2011-2013 days but many people are stuck in that time period STILL.As I finish my licensing study, I'm very grateful I chose this route as opposed to being a one trick pony.Wholesalers did themselves in by their method of operating.  

You could read 100 books and still need to learn more because certain things must be learned through trial and error.