I imagine the Cowboys cheerleaders would probably be the most popular and therefore profitable group, and there are numbers out there that can give us a picture of what they earn, plus a figure given for squads in general. A few quotes from
a 2010 article:
While cheerleaders don’t bring in tons of money to an NFL franchise, it is reported that a squad does bring in an extra US$1 million per season...
One of the ways that the Cowboys have marketed their cheerleaders is through merchandise. In addition to an annual swimsuit calendar, the Cowboys also run a camp every summer for aspiring cheerleaders where participants pay US$189 for the three-day session. The team makes a reported US$500,000 per season through appearances, as they charge US$200 per hour, per cheerleader.
I do love how a million dollars isn't considered tons of money anymore.
Saw another article that said the Cowboys cheerleader calendar for 2013 was expected to sell 200,000 copies. At the price on Amazon that's $3.35 million in revenue for calendars, plus the half million for appearances.
Then there'd be the indirect revenue... creating good memories for kids who meet them at events and helps them grow up as fans of the team, drawing horny male football fans to events, being able to splash sexy images in football commercials and during games, having them as halftime and two-minute warning entertainment for 70k+ people, not to mention being able to have a big team presence at events without having to take up the time of your players.
I have a hard time embracing an argument that the small amount it would take to up them to minimum wage isn't justified given the amount they bring in.