Verify that these match the promotional materials and agreements.Completion Timelines and Delays: Understand the projected completion date and any potential factors that could cause delays. 

If you send the security deposit disposition to the address they rented from you with ADDRESS SERVICE REQUESTED written in the area between the address block and stamp you'll get a postcard back with the details if the mail is forwarded. 

Tenant decides not to pay and use security deposit for last payment (not allowed).

As the seller, why would you return the deposit?

Are the prorated rents being given to you (along with deposits) or is the seller keeping it? 

They have many lender relationships and find the best lender (based on the criteria you match to). 

My math matches yours. 

The deposit we require is NOT earnest money.

However, another option is to call a few local credit unions and banks and see what options they have, they might just require you use them for your operating account and some might even require some deposit minimum too.

We decided to keep their entire deposit of $2000 and bill them the rest.