If you do, a tip is to flip inside an S-corporation as the income is viewed as more legitimate and easier to use with as little as 1-2 years of income to use it for qualification purposes.

When people are trying to ascertain who wrote them, what I do, am I legitimate, can I perform, etc an answering service or personal assistant hasn't always produced the results I desired.

Any legitimate self-employed person can do this.

But shouldn't their be a legitimate business out there that where a "motivated seller" can just hook up directly with the buyer and cut out this unnecessary person who is just taking thousands of dollars for doing nothing?

Not including the wasted time and effort to do it.I could also ask the mailman to get his RE License to legitimately get paid a referral fee.

I think that I could legitimately mentor and/or coach someone (or multiple someones).

Direct mail is a legitimate and legal form of advertising (assuming your message and imagery are not unlawful or offensive).  

I know legally you can assign and there maybe legitimate cases to assigning but if you are systematically flipping paper that seems misleading at the start.

This opportunity came from a credible source - I've bought and sold a LOT of properties with this SOURCE so I know this bulk REO list is legitimate.

To be legitimate you have to follow all the laws.