Merlin for Mage seems like a gimme; Dave had a really cool rundown of what that might be like.
Puck for Changeling, perhaps. There are a lot of iconic fairy tale characters to draw from.
Hunter is a bit trickier because they don't tend to live long enough for this sort of thing...unless you make Van Helsing an independent ghoul of some sort.
I imagine there are a lot of characters you could drawn on for Geist, but I can't think of any off the top of my head.
No idea for Mummy. A lot of them are Egyptian kings, which doesn't fit the cosmology.
Lucifer for Demon...or any number of named demons from Christian apocrypha and Middle Eastern mythology.
Beast could have any big name monster you can think of. Grendel would be a good one.