Thank you for explaining what O.P meant to the understanding of everyone about what an I.P game means, and as such, I would have also like to ask, How will the profits be generated form these IP games? Since the majority of the IP games you suggested are all adventural games, such as Spider man, Sega that makes somehow entertaining, and wants wants to play more, unlike casino games are are designed basically for profit maximization.
Honestly, this question should be directed to the OP, he might have more idea how everything would work. In the meantime, IP games and the original owner of the brand must have an agreement before game providers use their characters to create a casino game. If game providers do it without seeking the consent of the original owner of the characters they may be sued to court.
A clear example of this is Axie Infinity, which became popular for its P2P a few years ago. I think a casino would benefit a lot from this, since profits are guaranteed in P2P by charging a slight percentage to its players. It also has other factors that can make them attractive and profitable, such as sales of skin, tools, weapons, although it is an artistic and mechanical challenge to include this type of games so that it does not stray from the essence of a casino.
I think it's possible for a casino to have 100% original content that attracts and keeps its players engaged.
And regarding licenses, this is always done prior to launch. They can be temporary or permanent exclusives, depending on the developer and the contracts signed.