I think I've found good 15mm miniatures to represent Aslan here. Sure, they're supposed to be "bear men" but they do look somewhat feline (or, at least, leonine), and with a little bit of paint-work they'll probably be good for Aslan.
For the human crew (and semi-civilian human opposition), I might use the GZG Armed Civilians or Free Trader Crews - which do you think will be better?
I'm also looking for a good (GZG or something with a similar price-tag) 15mm set of figures to use as generic human military or paramilitary opposition.
The Aslan-Looking minis from Stan Johansen Miniatures:

The Free Trader Crews from GZG:

ATV from GZG:

Armed Civilians by GZG:

I'll probably end up ordering 10 "Balards" (i.e. Aslan), either 12 Free Trader crew or a Platoon (24 figures) or armed civilians, an ATV and maybe a platoon (24-32) or so of Human military opposition.