At the end of the day the biggest risk you face is losing your earnest money deposit when your offer gets accepted, but you shouldn't have to risk that because your lender is too lazy to look at the location, condition, ARV and proposed price for the deal

Preconstruction is all about putting chunks of deposit down during a stretch and banking on potential appreciation.. with the option to assign which is a huge market at the momentResale you can be building equity from rental income including appreciation.. but have already invested a lot of capital 

Also, make sure to get signed Tenant Estoppel Statements that state how much rent is, how much credit (for mowing the lawn or whatever else), the amount of security deposit, etc. 

Often times they demand the $10,000 up front in a non refundable deposit, so that if you back out they are still covered.

Do a 1031 exchange of your cheapest 2-3 properties for one more expensive property to open up a couple slots.

Sometimes I require a deposit equal to 1.5X the rent.

If it’s really outside the seller’s control, there’s not a whole lot you can do other than maybe walk away and get your Deposit back.

They can role closing costs into the loan so he really only needed a few thousand for the earnest money deposit.

They accepted my offer over others because of strong finances and ability too close, but now are requesting a loan commitment letter even after contract has been signed and earnest money deposited. 

You should certainly be asking for the leases, the security deposits and the Tenant contact information.