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. 

@Jessica Seppo,Many people take the cost of an LLC and funnel it towards more insurance and an umbrella policy.

The cost associated with insurance for not having 20% is peanuts compared to what you potentially can do leveraging your down payment. 

As mentioned take a smaller cut to complete a deal if necessary.

How much will this unit cost to renovate?  

I would include servicing costs of the loan and licensing costs.

STAY away from them at all cost.

Invest in Fix-and-Flip Properties:Use the $50K as a down payment or cover acquisition costs for a non-recourse loan (required for SDIRAs).

What costs/fees should I look out for?

The type of the neighborhoods where his properties were located didn't fit in with my plan but he did well and the purchase costs were low.