Being part of this industry and continuing learning counts as wildly successful for me!

Most would be minimum 100 unit properties or higher.If there are 100 buyers looking for 10 units but very little out there it is a wild goose chase for a commercial broker to find it and eventually get paid. 

But your answer to your question; they just take a Wild *** Guess, most of the time.  

With only 1 unit the numbers would swing wildly from year to year and you would never know if that number was an accurate one.

The good thing is, even if doing work for people that will lead me on a wild goose chase, at least Ill be getting a better feel for the market and learning for my own investment opportunities.

The biggest wild card is the rehab since we have not seen any pictures.

Unlicensed brokers aren't held to any standard, can make wildly untrue claims, etc and not be held accountable.

It won't be the crazy wild west like last time, but interest rates and property values can only go so high before the supply surpasses the demand and the market shifts into the favor of buyers and sellers start competing with each other by lowering prices.You could purchase a small multifamily property here in Sacramento for $300k or less, see a positive cash flow of $500 per month, have the tenants pay the down the property for you and still make money when you sell it in a couple years at the peak of the market.

Not sure I'm wild about their overzealous moderation policies.

When you can do this, the money or capital will come.Now, I or anyone might have told you get a money guy, partner up, go wholesale, work with seller financing or any wild and crazy idea, but you're really not ready to go there starting out, your question itself indicated a lack of entrepreneurship skills.