The vast majority of my bookings are on Airbnb and I made the amateur move of paying the flat fee to Homeaway when I signed up.

I have excellent credit and sufficient funds. 

I plan on living with my parents for the next 3-4 years while aggressively investing the vast majority of my post-tax income.I've always been interested in real estate and think that it could play a large role in my portfolio.

There's something like 25,000 agents in Denver, and a small fraction of them are doing the vast majority of the deals.

The government has owned the vast majority of land in all of the western states. 

A flip is a business, so it is subject to ordinary income tax.The IRS does not care if you buy a house, improve it and resell it or you buy bread, mustard and lunch meat and make sandwiches - to them it is the exact same business model.You can search the vast number of writings I've done on this subject on Bigger Pockets.I agree with your CPA in all aspects and here is why.Running it through an LLC:  If this project comes in at a loss, how is your investor going to prove out their share of a loss or report it? 

I see my six isn't sufficient. 

First, you can hire someone who has vastly more experience than you have, and at a level you can never expect to accumulate.

You Can Catherine but you will come up invariably upon the Self Sufficiency Rule (or SS Rule).

Generally, the normal documentation of the transaction is sufficient proof of the “per se” exemption.