I stupidly did not have a must close by date on my contract, they have offered to give  me more escrow to extend the closing, and I have this opportunity to have the contract amended I believe, and add it must close by _____, and demand more escrow, to protect myself.

If lot value is the majority of the total value now, the highest and best use is to build new, above any flood elevation, not to extend life of the current improvements.  

I never look at how much I'm paying in interest over the duration of the mortgage, all I care about is the rate that I pay on the loan and the rate of return I think I can make from my investments .

That way I’m not over extending myself by developing them all at the same time.

The longer the duration of the project the less viable hard money will be for funding.  

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.