CM sigilyph is an absolute monster I can say from plenty of experience using it. I think psyshock's most important trait is to beat easily smash haze cryogonal who would otherwise completely wall you, munchlax isn't that much of a deal, sitting only at #43 in the June usage stats. I think roost is pretty necessary, though. Maybe slash HP ground with psyshock, it seems to make a bit more sense as then you can just choose what you're walled by, steelix or cryo.
Hitmonchan looks fine (actually, it's pretty similar to medicham).
A man can no more diminish God's glory by refusing to worship Him than a lunatic can put out the sun by scribbling the word 'darkness' on the walls of his cell. ~C.S. Lewis