But also applies to all surfaces at stores, mailboxes, etc.

You need to have written policy in how you deal with tenants and apply that policy across the board.If you allow pets under a certain weight, they have to be allowed across the board.If you have a policy that all tenants must make 3 times the rent, then all tenants must meet that.And if you have a policy about waiving late fees, or reducing rent, or waiving one month of rent, whatever it is, you really need to apply to all.When landlords get into case by case basis with a different rule or decision for every tenant, that's when you set yourself up for a fair housing violation.   

I was a credit manager involved in credit and lending in the commercial area and understand the world of ratios, like DTI, how it's applied, how rules are bent.At one point, like you, I was up to my third property, triplexes and a SFR, all cash flowing, when I went in for a refinancing.

I've received word from title companies, and lenders that the Houston area restrictions do not apply to real estate or building development.

.) - consult your attorney to see if this applies in your case.Unless there's a valid contractual reason for backing out, your deposits are at risk. 

But due to the health crisis, I will let it default to M2M until the crisis is over, and crisis is over when the eviction suspension is lifted.during the M2M extension period they still have to pay rent, and if rent is short you will start applying the double deposit to the rent until the deposit is depleted.Hopefully by then the situation is better where they can move out and part way amicably.I don't think I would do showings at this time, and this is a most likely a moot point as more and more states are heading to close all non-essential businesses.

Is interest applied to the entire missed monthly payment, the portion of the payment that is principal?

If someone says they are interested and they want to apply, that's great!

If you have a de minimis safe harbor election in place for the tax year and expenses related to the building structures subsystem are more than $2,500, the expenses would be capitalized.It might make a lot of sense to forgo the de minimis safe harbor election and apply the betterment, adaption, and restoration (BAR) tests instead if doing so doesn't jam you up in other areas. 

Consistency really is the key, and I'm certain through applying all that you mentioned I'll be more than ready to acquire that first deal in "NO TIME!"