Different areas have different rules but I keep it quick, brief, and electronic, no one knows why they were denied but everyone knows up front there will be many applicants and I pick the best, security deposits are non refundable. 

Keeps accurate records and ability to accept deposits etc.

You can literally write a check, deposit it and wore that money right before closing 2) They will use the minimum payment you are obligated to 3) Lender specific 4) Lender specific

Each vacancy will cost one months lost rent plus leasing fee (0.5 to 1 month) plus any turnover costs over and above what you can claim from deposit.

leases with security deposits are in contract. closing date is june 30th so there would be no pro-rated amount for rents. what can i do to guarantee they are up to date and i dont get stuck with someone elses problem?

As-is is the acceptance of the property in an as-is condition, you can broach your agent about renegotiating but be prepared that the seller will push back and decline or you can walk away and he'll keep your deposit money. 

@Nathan G. what about security deposits?   

Collect rent and deposits.

You may be able to back after them for your costs in straightening this out.Did you get any letters of indemnification from that seller and tenants that stated if there was a security deposit, last months rent, who was in the apartment etc etc?

There are a handful of things that will make an on-market wholesale difficult, including (but not limited to):- the fact that any sellers agent worth their salt won’t allow your “and/or assigns” language- you need to provide proof of funds with your offer to get the initial offer accepted - your timeframe between accepted offer and when your second deposit will be due is very short and gaining access to the property can be difficult