I have come across several companies like Legal Zoom, Zen Business and many others, some which I think want to overcharged me.  

Reporting the mortgage interest on the return should be done with care, as the IRS does not have a copy of Form 1098 under your SSN (or EIN if business) reporting the interest.

I'm sure they price the product is based on the potential returns if an investor works the program diligently.

To ensure you can apply the tax deductions against ordinary/active income, you have to materially participate in the STR business.

Normally, for comparables, you want to look up recently sold properties within a half mile to a mile (the closer the better), in similar condition, square footage, amendities as the end product, and the same or similar bedroom/bathroom count.

I work with some of the best in the business.

He wants to use the 50k to jumpstart fix and flip business 

In general though, you're able to directly offset your income from the active rental activity with the *losses* you take from the business, but once the business becomes profitable, this would also add to your taxable income. 

People like to do business with people who do business, present a good deal, and you will have a long term buyer to work with!

@Courtney Olson I did this for my candle business but it could work for real estateMaybe offer Step Up  Payments too, as long as the number works, and hint at it helping wiht inflation and maybe combined it with an interest rate that is above typical inflation.A combo of something like 4% inflation to keep your same spending power as the years go, and we increase the payment by $25/month every 12 months so your spending power stays the same and you get a bit of a raise every year, then we could do a balloon payment in 10 years to settle the rest.Something like that could be an option.