I found a buyer who entered into contract with the seller on 3/4/18.

The contractor cant "rip you off" if you agreed to the price and he completed the work in the contract .  

Informally or should a contract be drawn up and presented?

They are going to ask for a plan and bpo's, contract (if available), liquidity or cash you are bringing to the deal, anything you might haave to put up for collateral and a few other things depending on the lender.

Sign a contract to purchase then close on it.

And it sounds like there would not be any (legal) problem with beginning and ending rental contracts on the 15th/14th-- is that correct?

(if you would like to learn more about how we find, and track off-market deals check out https://www.biggerpockets.com/forums/311/topics/556219-flip-in-the-historical-district-of-downtown-tucson ) Once under contract, our construction team put together a comprehensive estimate for the remodel and our investment team began running a financial analysis and a market CMA.

We're going into contract on two duplexes, with one in her name, and one in mine, for financing reasons.We're looking to meet with an attorney and tax planner, so we'll absolutely ask these questions there as well, but I wanted to ask the forum first.I work a full time w2 job.

If that's true, then you better get it under contract before the seller finds this forum.I'd say it's also a bit naive to expect the house to be perfect beyond pressure washing and carpet cleaning.

My experience with them on the buyer side is over worded contracts but pretty smooth transaction and listed slightly above recent comps which is typical for our market.