I'm trying to get ideas on how I can word the letter in order to remain truthful and sound good at the same time.

I had a guest that waited 30 days for a credit to his AMEX for a refunded security deposit.

Overseeing and hands on in the BRRRR is my day to day.

Yes, the day before they are supposed to arrive.

When I spoke to them, they were horrified and had assured me they had sent payments, same way as in the past.

My realtor seemed a little miffed, but I have 17 days to get the appraisal done before closing and my MLO is confident we can get it done in time

Same thing map out as your REI grows.  

They do require patience because they are similar to construction where they can take 60-90 days on average to close.You cannot do the work you need an approved GC or builder and typically required to get (3) estimates from (3) local licensed GC/Builders.  

I own a 1 bed 1 bath unit overlooking downtown from a huge balcony, 1 car spot and free heat and hot water for $2200.00 and it has been sitting in the market for 60 days now. 

Ensure that all contractors base their bids on the same scope of work.