Make the letter/receipt professional and polite.

I NEVER offer an EMD, I just include a POF(proof of funds) letter so they know I have the funds to close.

Does written mean actually mailing a letter to them, or can I just print a letter - sign/date and hand deliver?

If you have your property under an LLC you cannot DIY represent yourself anyway.Also,  consider approaching your local media outlet or writing a letter to editor of newspaper and contacting your representative government officials to let them know that you are a landlord who has a tenant who is able to pay rent but has taken advantage of the terms of the emergency eviction moratorium and refuses to pay rent.   

Effectively creating a small balloon payment at the end of both 30 year loans. 

We have a balloon payment due in 15 years on our mortgage.

I know Kiewit will provide a letter of employment saying where your job rec is as well as how long you've been there, salary and all that good stuff. 

Have Letters of Administration been approved by the court and issued to the PR?

Most listing agreements have a provision for cancelling a contract, and that usually involves sending a letter to the broker via certified mail.

We sent all of our tenants a letter stating that due to the uncertain times, we would not be increasing any rents.