So, this is my 10% contingency on the estimate.Then, if there is a major item that I'm not confident in the cost, I may add an additional contingency there. 

A few additional things to consider between the two loan types: prepayment penalties, probability of closing, points/ fees.... and vesting (LLC or personal). 

But it's best to jump in feet first.One thing that's helped - I've been able to grow our organizers by three additional people - we have a US / Korea Liason, a bilingual research analyst, and another coordinator.

Real estate websites such as Realtor.com, Redfin, and Zillow can give details on recent sales in the area.Use Real Estate Investment Calculators: Take into consideration utilizing additional online real estate investment calculators in addition to the BiggerPockets rental property calculator.

Should I add it as an addendum? 

Additionally, the national debt is becoming a thing.

I also see that some have additional reader fees that come with it. yikes! 

The goal was to initially do a small renovation and add an additional room and bathroom to the already existing older home. 

Additionally, with a median home price below the national average, Cleveland offers affordability that may be attractive to some investors.

If you want to protect your friend's capital as if it were your own, you'd want to:1) Secure the loan with real estate in the form of a deed of trust or mortgage (depending on the state the property is in)2) Obtain property insurance binder with your lender as an additional insured3) Obtain a lender's title insurance policy protecting them (different than an owner's policy) and transfer all funds through an escrow closer or real estate attorney (depending on the state, the requirements for closing may differ)4) Use a real estate attorney who also practices private lender law in the state the property is located in.