It's only had a few episodes so far, but Legion has packed in enough reality-bending weirdness to spawn a thousand theories. But before theorizing about what it all means, let's start with who everyone is, because the Summerland residents are still pretty thinly sketched. Are Kerry & Cary from the comics? Most of the characters on FX's Legion are original creations, and Cary & Kerry Loudermilk are no exception. There's no characters by that name in Marvel or X-Men history, nor are they obviously based on any one particular storyline or character from the comics.
But like Syd, Melanie, and the other new characters introduced over the course of Legion, there may be some comic book allusions hidden within the characters that will help demonstrate their role in the story. So far, though, there's not too much to go on. Cary, the older scientist played by Bill Irwin, is clearly the resident technical expert. According to FX, Cary is a "brilliant geneticist," and he's the poor guy tasked with testing David's brain in every episode, and it hasn't worked out well for his equipment. The X-Men are certainly filled with tech-savvy geniuses, like Beast. But since Cary is not giant, blue, and furry, it seems his intellect is the only real connection he has with Hank McCoy.
His younger counterpart, Kerry, is even less sketched out. FX calls her "a mover and doer who is the kind of person that’s never satisfied with a green pasture," and she's certainly more of a fighter who's always moving and training. In fact, she was so tuned in to just Cary that it almost seemed like she might not even be real/visible to everyone until the moment when she spoke directly to Syd in "Chapter 3" — telling her to get away from the work she was doing to help Cary with his tests. Even stranger, it seems that her power has something to do with her relationship to Cary, because in another scene, she walked right... into his body, and became absorbed by him. Clearly, the characters have a very close connection — I mean, just look at their names — but this hints at a deeper connection.
Does that mean Kerry has the power of being absorbed, or that Cary is somehow projecting her? Famously, X-Man Shadowcat, AKA Kitty Pryde, has the power to walk through solid objects and people... but even she can't be absorbed by someone else. One mutant from the comics, Multiple Man, aka Jamie Madrox, had the power of duplicating himself, and then the power to reabsorb the copies he created. While the clones did have their own personalities and in some cases, tried to break free, the copies were always identical to him. Not much like Cary & Kerry.
And with their age differential, it seems possible that they could be a father-daughter duo. Again, not much evidence of any similarities to specific parent-child relationships in the X-canon, but often mutant adults do have mutant offspring (see: David Haller, canonically Professor Charles Xavier's son), so it's possible that Kerry is some kind of projection or extension of Cary, or maybe even a memory of someone close to him. Surely, the extent of Cary & Kerry's connections and powers will become clearer as more episodes of Legion pass, but so far, these characters may have some small inspiration from the comics, but you won't mistake them for any preexisting characters.