Beware of trusting people with a profit motive.

Did you ever get any sort of agreement template that you ended up using? 

I am very serious and motivated to buy and revive my city.

That is a great motivator for Seller to work with you, but expect a negotiation. 

Anyways, my opinion is that you are clearly an intelligent and motivated worker.

So, you while many unexpected repairs are not avoidable, if you know where the flexibilities in your project are you can manage the project to completion by making these sorts of decisions along the way. 

Lenders are motivated to see the project succeed since they’ll benefit from the upside.

Hey Miguelli,My advice...1) Do not use a HELOC unless you are doing some sort of value-add activity.

Actually, above that I'd love to see an opt-out clause if X of the raise goal is not achieved before closing.One may try to say it's a bait-and-switch of sorts, on risk levels, to close w/o the full funds IF the chances of quickly closing out the remaining raise are not realistic.

Assuming since you're asking, you're not interested in some sort of traditional financing?