Funnily enough I do actually own a complete Apple IIe card (including box and manual!) and a compatible 5.25" drive
I havent powered it up as of yet, but do intend to install it into my LC475 eventually - problem is, I lose my ethernet in the 475 when I do it, and to be honest, although this is probably the way I will end up doing my real Apple II'ing, its not as flexible as a windows based emulator (as the 475 isnt exactly modern these days), and so to start I'm going to go with something windows based to get back on the bike.Ultimately I'd like a real Apple IIe (like the good old days), but they are hard to come by in my part of the world now days.
Anyway, to answer your question about the IIe card and hard drives - you can partition the LC's disk and create a ProDOS partition which will be recognised by the IIe card (and the Mac) - I have a 20MB partition all ready to go for when I install the card - according to the manual I'll be able to boot from it and access it like a normal A2 hard disk - its also a good way to get files to/from the IIe side of the Mac.
Cheers,