A good bet for a Catalan or Occitan Speaking colony would be to have a Catalan or Occitan colonization group specifically wanting to establish settlements of Catalan or Occitan colonists. They would probably be independent ventures set up locally, with national governments more focused on national colonies that would probably be dominated by the majority group just by virtue of numbers.
The position of the Catalan countries facing into the Mediterranean doesn’t make a great position to send people across the Atlantic, but Occitania might have better luck with their Atlantic coast, maybe using Bordeaux as a launchpad for any colonial ventures.
The easy option for these Occitan colonists would be to settle in an area already claimed by France, maintaining a connection to the mother country giving them easy trade and protection instead of trying to go it alone in some unclaimed plot of land, but that also runs the risk of assimilation into French-Speaking society, which would defeat the whole purpose
So I think that an Occitan colony would have to be within the wider French sphere to a degree that they can maintain these connections, while being separate enough that they don’t have to worry about cultural assimilation.
The more remote parts of New France away from the major centres in Quebec and Louisiana could be an option, maybe around the area of OTL Detroit or Winnipeg. If they can have a large enough population and primarily-Occitan culture by the time of the handover to Britain in 1763, we could get a sort of Occitan analogue to Quebec, an sort of linguistic island surrounded by English (and to a lesser extent, any local Amerindian languages, depending on how history goes with them)
