Extend the Contract and Wait, or Cut Losses and Move On?

[Devrim G.]

Hi, I'm hoping to pick your brains a little bit. What would you do if you were in a position as below? 

Thanks!

Deal Description:

4 two-bedroom multi-unit property built in 1940's, in South East Washington DC. The rentable area is 3400 sf and there is a 1100 sf unfinished basement with enough height clearance for a basement unit in the future.

Sale price: $599,000

offered and contracted price: $599,000 and 2% closing credit from the seller

Appraised price: $599,000

Down payment: 25%, interest rate locked at 5%, conventional 30yr mortgage

rental income=$1,300 per unit per month, $5200 total per month

mortgage, tax and insurance payment: $2,900/mnth

Three inherited section 8 tenants on month-to-month lease, one vacant apartment

Utilities other than water paid by tenants

Immediate repairs will cost $10K, including preparing the vacant unit for rent. We have a contract in place that will expire soon. Should we extend the contract and close this property?

Edit: I have to add, the fact that contract expiring is due to owner not being proactive enough and taking their time collecting all the documents/requirements to be able to close.