I wonder if the interest rate on the HELOC will be too high to make the monthly rental rate practical for a renter.

While this is a violation of the covenants of the deed of trust or mortgage instrument, and theoretically (if the note holder becomes aware) the note holder can accelerate (demand full payment) of the note, in practice this rarely happens.However, there are risks for both the buyer and seller in a subject to transaction.  

You just need to practice.

Individuals who have received a CPA designation are trained in generally accepted accounting principles and best practices (including online tools).

Is this common practice?

Just be mindful that he has his practice set up remotely.Best of luck to you in your search.

The ground under there would never be anything but bone-dry, as the rain practically never soaked down past the footer level.That was also my passive solar house.

They give some practical advice on how he approached people to ask for real estate investments.- You can start off by renting out your car using a platform like Turo.

And honestly, it was never any issue in my 12 year practice 

.#4 Practice using a rental calculator to calculate your numbers.