Finding metroids in an icy environment only seems impossible until you play Metroid Prime.
I’m not certain on the exact timing of Metroid Prime, but it’s clearly before Metroid Fusion, because the Ice Beam is a thing. After Fusion, you can only have Ice Missiles. Either way, though, there are definitely still metroids during that game, and some are even ice element. That said, the elevator said that the reason this place is so cold is because the climate control system is malfunctioning. It’s totally possible a metroid was here earlier and then the place froze over. (And we know that the Federation had metroids during Fusion, so of course it’s fine if they’re here.)
I commented that the lady “looks young” because if she was in charge of the facility, I’d expect her to be at least in her forties, if not older. Nobody gets to run a place this expensive at that age, unless she invented practically all of it, like the folks who made computer companies in the last century. And, well, I don’t expect that’s the case. If she is in charge, it’s more likely because she’s the only person who survived, rather than because she founded the thing. I’m more guessing that she’s the daughter of the director or something like that.