He had the demo done, leaving the garage standing, because a neighbor had expressed interest in buying the property for the purpose of using the unscathed garage for storage and he could therefore give up his current storage units. 

If I were in your shoes and having a good 2016 sales-wise, I'd go ahead and file my taxes in Jan/Feb 2017 and refinance at that point when I could show the lender those awesome 2016 tax returns.

You're in quite the situation but I would say put yourself in the lenders shoes.

If I were in your shoes I would start an LLC and then create a  basic loan agreement that you can use to borrow money from each person using the same contract.

Big concern if I were in your shoes is that my family gets offended pretty easy so I wouldn't press too hard if they feel like I'm trying to cheat them out of their inheritance.

More of a concern for me would be the lack of the added storage an unfinished basement gives to a tenant.

I am looking to meet someone who has been in my shoes and can help me get started.

If it's middle class income neighborhood.... dress casual, and if it's really high end or maybe commercial... you get the idea.Personal thought that may or may not apply:  Don't wear fancy shoes.  

One piece of advice I always try to give to people in your shoes is - use your successful day job to your advantage.

There's also a BP webinar coming up on it that I'd sign up for if I was in your shoes.