I don�t think they'll do it. They would have to make dialogues/stories/romance for any additional companion. And seeing how Halsin (a character that wasn't supposed to be a companion) ended up... I would say nope. :p
But there are mods that make NPCs playable (sort of) if you play on pc. I wanted to install one of those but couldn't because I play on my Steam Deck and if modders don't leave the code to manually install I can't do it.
