And the finish date will be extended by a month , since we have other contractual obligations . 

If you need to extend your close date to give you time to have repairs completed and inspected.The easiest way forward, if you have documentation that your agent agreed to verify the repairs were completed, is to call up his Broker and tell him what happened. 

Plus, on the HELOCs there’s a time period when you need to pay only the interest, which I do not advocate for for an extended time period, but in the beginning that can reduce the stress while you are acquiring/rehabbing, renting out and refinancing.

If I can not sale the contract in the allotted time how can I extend the time on the contract?

Tenants are not the ones paying, so if we have another extended govt shutdown (entirely possible imo) it may delay signing lease with the tenant like I did.

I'm about to extend it till March 29th or longer, do you know any specialists in that area? 

The person doing the paying can dispute the payment (not sure for how long, but I know it's for an extended period of time) and the person receiving the payment has little recourse for the dispute.

I also installed high efficiency forced hot air systems rather than electric and extended the driveway to accommodate spaces for all three units which I include in the lease.

My tenants did mention some new cracks in the ceiling, but I do not know their magnitude at this point or if they extend down any walls.

My thoughts are shorten your bridge period to mitigate risk (uncertainy of the markets down the road), and re-finance sooner rather than later - or, see if you can negotiate in an option to extend with the Seller.