So if hit 3 out of 4 - appreciation, principal pay down and tax benefits that was acceptable to me. 

Certified Acceptance Agents are located worldwide.

The estoppel is a form filled out by the tenant, then confirmed by the Landlord, and then accepted by the Buyer.

When he purchased a house in 2021 we closed in 35 days from offer acceptance to closing date despite the loan being for $3M @2.75% 30 years.  

Quote from @Melissa Rivera: When a tenant is late, your policy should be that payments must be in full and with a money order or cashiers check.I would contact the tenant and tell them you will not accept or cash the personal check.

Some sellers will accept that in a contract and others won't.

However, I am guessing they are your registered agent for your LLC, in which case they are authorized to accept mail and serving documents on your behalf. 

In many places, giving proper notice that you're not renewing the lease is perfectly acceptable, but specifics vary by location.Another option to consider is "cash for keys," where you offer the tenant a financial incentive to leave early.

It seems this is the only way you are willing to accept the materials covered in your training can be found online.

For illustration purposes perhaps that technique would be more accepted when you are a vendor mowing a lawn or clearing out junk as a one time engagement but as a property manager there are significantly more pitfalls and potential instances of liability exposure.