We got started, but they hired an appraiser and charged me $750, while typically appraisal costs around $500.

Additionally you can do a cost segregation study and get a lot of depreciation benefits to offset the rental income (and potentially other income).  

I did not want to spend 50K on doing separate meters for where I have my rentals it would cost me this much.

How much did the rehab end up costing and how long did it take to complete?

The primary risks at this point would be       1) to your lender, the risk of a margin call.       2) To you; underestimating the true cost of a project and cost overruns      3) To you; legal risk of securities regulations if you partner looses money. 

I had to go that far away due to the insane cost of real estate in Boston, so I fully understand the predicament.

@Martti Eckert in our opinion, you'll need to be really familiar with construction, including costs, or be able to find somoen on the ground you can REALLY trust (but still verify).

Then there is the time element with holding costs.

Are there any rehab costs?

Not sure the cost of this for you but I feel with hot tub and fireplace you already have a lot of warming options and not get much additional revenue.