H2Ohm really is that bad, yes. Only one other Pokemon in the game has a number in its name, and that's Porygon 2, who might be the only Pokemon it could make sense on. In addition, H2O is already an abbreviation and when spoken, H2Ohm is very harsh-sounding and grating. It's just not what it would be named if it were a Pokemon.
Crevolt is ok, it reminds me more of Crevice + Volt, and not that Crevette de Volt thing it should. It doesn't remind me of anything remotely watery, and really isn't that catchy. It doesn't flow. Not sure what else I can say. Shockateur isn't that clever, really, as the saboteur reference is largely lost. Furthermore, the use of shock is too blunt and the way it rolls off the tongue isn't as exciting as some other entries by other people.
It's difficult to rate some names, because largely it's how the word sounds when spoken aloud that determines how well it seems to "feel right" or "fit" CAP10. When submitting these things, try to say it aloud, and do so while not looking at the art. If you can truly conceive something close to the art from the name (most people can't and just pretend they can), then your name might fit.