I got some questions, that are mainly about Mordheim, here are my first 2:
Slings; range 18, fire once, fire twice at half range when not having moved.
Nimble: may move and fire with weapons that normally aren’t allowed that:
Combine them: can you move your normal movement and then still shoot twice if at half range?
Can you buy barding for a Bull Centaur hero?
I would say no to the slings question. The sling rules aren’t a normal case of “move or fire” (like a crossbow), just an effect that’s different if you moved, which is not covered by the Nimble rule (to the best of my knowledge - I don’t actually know where it comes from). If the rule was “always counts as stationary”, then they could combine, but it seems to be refer specifically to things like crossbows which are move or fire.
Bull Centaur question:
1) Do you see the option for barding in their army list entry?
2) They aren’t cavalry anyway, so even if there was some way to “generically” buy barding, they wouldn’t be able to use it.
As Thommy H has said: It’s referring to mover or shoot weapons. If you normally can’t move and then shoot, you now can. The way it’s worded is key. It says they may move and shoot if not normally allowed, not they always count as not having moved for the purposes of shooting.
Secondly, you can’t buy barding for them. They aren’t a mount and have no option to buy it.
Hope that helps.