After researching the variety of real estate investment options, my wife and I would like to purchase vacation rentals. 

For a variety of reasons (we are set to close in two days, we have not yet proven ourselves to this investor, etc.), I quickly responded that we could and he responded with that is what they would prefer, which I totally respect.This is our 4th flip and we have not used any of our own money for purchase or repairs. 

I can suggest Gateway Mortgage (they have a wide variety of lending options).

Having done a variety of RE investments, notes is my favorite.

I've worked on a variety of projects from small TI's, to airports, prisons, office buildings etc.

Not too expensive and cover a wide variety of topics.

There are a variety of loopholes if you decided to leave sooner than one year, but you would want to speak directly to a lender to figure out all of those. 

I think it may be best to contact local builders and obtain a variety of bids on what it's going to cost to construct this complex on a "price per square foot" basis.

Oak was only rarely used in US housing built in the 1900s as framing lumber, for the simple reasons that most varieties of oak don't tend to grow straight, oak grows much slower than most pine species, and oak is usually extremely heavy.

Be prepared that the members of your team may change for a variety of reasons.