Even though the X Parasites can accelerate the growth of a hos organism, they still need the appropriate nutritional value in order to do so. In Lavos's case, it needs to allow the planet to grow before it will have enough to reach maturity, so the X will just have to wait for Lavos to finish what it started.
Can that thing even hear her? 'Cause if not, she must love to here herself talk.
its just exposition, all villains love to hear their own voice for the viewer's sake. That leads me to wonder if X are immortal. They can process data organically, meaning they probably share a common memory, so even if one of them dies all the copies of it have the same memories and thought patterns, so its as if it never died from an outside perspective. They're like a giant version of bacterial plague, unless every single one of them is destroyed they will repopulate. SR388, the Metroid homeworld, was probably completely assimilated once the metroids were rendered extinct there, possibly within a few days. I've been theorizing too long, sorry.
It's a good thing that she doesn't know how to create Gates. Growing to the age at which you are at your maximum potential power and practicing all your life with that power up to that point are two entirely different things. Sure, she's got the mana pool to do things like open Gates left and right now, but she wouldn't have the experience,like Magus.