You left out Dennis James, Chad Nichols, Milos Sarcev, and a bunch of others more prominent than those guys.
And they make whatever the person enlisting their services can afford based on their sponsorships, coverage in the magazines, guestposings. There can't be a flat fee for a pro BB client. For Joe Blow? Yeah, no doubt, they squeeze them. But for someone who's got an IFBB card, they have every reason to keep that person around, so they probably get free plane tickets, meals, etc. rather than lump sums every 2 weeks.