While I don't know of any pets that can build combo points you can get with GetComboPoints('pet', 'target'), and I'm pretty sure you can't see enemy combo points, it makes sense to centralize cpoints.lua with one player frame for all instances. That way you're assured the unit passed is always 'player' getting combo points for something no matter what oUF spawn is using self.CPoints.

Of course this frame would work with vehicle swapping too.

The combo points element doesn't do any unit checking, except to see if a vehicle unit exists. Making CPoints move to a possible existing player frame isn't really necessary. It will however be changed to update on target switch, so this shouldn't really be an issue at all.

My bad. I forgot for as second that events don't care what frame (unit or otherwise) they're registered to, it's oUF that ties a frame to a unit. Now that [cpoints] uses cpoints.lua and cpoints.lua is fixed then it should be all good.