Think of it like this:

The production company is responsible for figuring out all of the logistics of the fight (who's going to fight, where they're going to fight, who's going to televise the fight, marketing, promotion, etc). With that responsibility comes control over how and how much everyone involved gets paid.

Floyd, Showtime and UFC all have the capability to act as a production company for a fight night of this scale. I don't think Conor does because he's never had to do much more than be colorful and fight bc UFC does the heavy lifting for him.

If he's got a production company now, I bet it's mostly to handle some of his own promotion. He's under contract with UFC though, so I don't know how much autonomy he could really have.

Since this is a boxing card, I'd think that Floyd and Showtime are ultimately sharing most of the production duties, with UFC taking more of a backseat role. I'm sure UFC is getting a cut somehow, since they "made" Conor and he's under contract with them, but it doesn't sound like they're in control of much in this fight.