Ziprent will write the lease, execute it, then get the tenant in the unit and collect first month's rent and deposit.

The vast majority of lawsuits against Landlords are for wrongful eviction, security deposit disputes, and Fair Housing Violations.

Laminate countertops can hold up pretty well and if damaged, will need to come out of the security deposit - lower cost product, so a larger percent of it gets paid for if damaged. 

I also let him know that I would need 3 months of bank statements showing deposits going into his account from the business.

And this is CRE, so it's cutthroat, it's no one's problem but your own if you lose an earnest money deposit. 

Others will collect first, last, and a smaller deposit.

So the total amount that should be paid will be rent for remaining days in month + security depositORrent for remaining days in month + next month + deposit - I don't know when would this situation arise.

I'll reach out to the lawyer in the meantime, but I suspect if they refuse to pay it, it'll have to come out of their security deposits when they move out?

At a bare minimum, I would require a written lease agreement and a standard security deposit equal to an entire month of rent.

If a buyer is coming down with a high-down payment and quickly making a large deposit into escrow fighting tooth and nail about proof of funds may be a red herring.Credibility is also a factor here.