So a lasgun isn't kosher, but a lasgun with attached bayonet is? The bayonet has an edge, therefore the weapon does!
I would allow crossbows for Moritat, but crossbows are rubbish anyway, excepting the Witch Hunters' stake crossbows. I prefer a composite bow, and even then I don't use it nearly as much as my sword. Mono arrows/knives are not cheap. Shuricats are right out; they're xenotech, and xenotech is heresy.
Primitive ranged weapons suck anyway. A Moritat is better off just buying a decent sword or axe and getting in close.