So to answer your question I have not came across a lender that would look the other way when flood risk is involved.  

Crafting your offer with terms that are important to them will always make your offer more attractive.

Can the BP family help me think of other costs involved (outside of buying and rehabbing and managing)? 

It's based on very specific conditions, seller type, market, and other factors that are too involved for this format. 

If there is anyone currently involved in the Opportunity Zone Fund process to benefit from incentive programs to defer capital gains tax please reach out to me.

As stated this would be my first investment property so there are nerves involved and uncertainties so take it easy on me!

This way you don't have to be involved in every decision while you're living OOS.

-If the sale involves a note, regular and timely payments on the note should be made, and repayment should be based on the value of the underlying property rather than the success of the land development.

I would suggest attending REI meetups, getting involved in the forums here, etc.

It will likely need many more involved parties, and each person creates more management challenges and more friction.