adults=1&...I have had interest from several people who want to "get in on the next one" . 

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In my two-bedroom unit, I have stated it has a max occupancy of 4, not more than 2 being adults. 

I was guessing that her parents (who I try to keep out of it and let the 'kids' adult) were probably not told everything from their daughter. 

And if so what else can I do to truly prepare myself to be able to invest as a young adult?

Start with the "unrelated adults rule".

The two adults are on the lease. 

Two adults means more household income which I find is safer if one loses their job.

So far adults don't have any issue sleeping in them either.If you get some, make sure they are rated for the weight for adults.

He is not looking place to live but scamming potential landlord, such as females.