Your examples are mostly still "faking" - faking consumer interest, faking popularity.
Companies do that all the time.
Companies do that all the time.
In the case of the dating website it is faking. Because there's no way you'll end up dating the fake profile
Not sure how it was in the case of Paypal, if it was a false order or they would just go ahead and buy small stuff then.
But in the case of Reddit and Rentoid, it's not fake. You're getting what you want. Links and the products to rent.
It doesn't matter if it's being provided by the founders, you're getting the service
Users may have been surprised to find out just how few other people actually existed. But I see this as legit. It would be like a big corporation hiring "Esprit Legal Firm" for their defense, winning in court, and hen finding out that the company was run by a single lawyer. Obviously businesses can't lie, but you're not required to list your own flaws either.