However, I’m trying to understand the key numbers, and which formula to use on it.

When you follow the link, he has this 1-hour long video explaining his backstory, the success stories, and offers a one-time investment for his "Free House Formula".

Curious about formulas when I see IRR, CoC and others what exactly is included, especially depreciation which I find is such an important part of real estate investing.

I will use the following formula to calculate the future rent at 5 and 10 years.Calculating:Five years: $1,000 x (1 + 2%)^5 / (1 + 5%)^5 ≈ $865Ten years: $1,000 x (1 + 2%)^10 / (1 + 5%)^10 ≈ $748So, in five years, $1,000 will be worth the same as $865 today.

I used the 70% rule formula, but after plugging in the cost of hard money lending, I'm having trouble estimating the profits.

You could look into the same house hack formula with a duplex or even a single family home where you can rent out the other rooms to people you know.If neither of these are options, I would start researching how you can grow your active income so that you can create more options for yourself in the near future.

Scott,If you stick with a proven STR formula, like we use for our clients, Sedona luxury STR's are getting huge returns.  

I have used and justified this same formula (though carpet better not cost 7k) in court and won several times. 

If the intent is to track actual and time-sensitive performance numerically, then IRR works much better.But, to a lot of us, time has more value than any formula can track.  

The formula I use requires a rehab cost amount in order to effectively analyze the deal and make a fair offer.