This is what kinda worries me about cross-gen evolutions being based on Galar forms. It'd have been much easier if they made them based on their original forms. I mean, I like the designs, but this could raise some issues unless they continue to support these forms in later games. (Maybe what they did in Let's go, where it's like "Hey, I'll trade you this form of whoever for its original version!" in a few different games across the series). Of course, that's most likely not happening because it's Game Freak, and they can't even support their entire Pokedex.
But at least, like you said, Zigs and Linoone are going to get forms.