I have X1, X2, and X3 installed on my computer and they get along fine. I think sometimes they go out for drinks at night when I'm not around.
If you want V-Vocal you don't need to install all of X2, just the base program. But mess with Melodyne for a while. You may find, as I did, that V-Vocal became irrelevant.
Be forewarned that Melodyne looks simple but it is
deep. For example, the Split Notes tool is what allows you to really tame vibrato correctly - flatten it out, emphasize it, etc. The
combination of note splitting and the modulation tool is what replaces the pencil.
You'll probably go through a "is this all there is?" phase, then dig deeper, watch the videos, and find out how much you can do with it.