Re: Conceptual problem about themes
You should think of a home theme as just a standard WordPress blog theme. It is no different other than a few new files to handle directories.
A member theme is a “BuddyPress” theme, and should probably be called that.
You should treat them as two entirely different themes, your WordPress theme should have the styles and images for just the WordPress parts and your BuddyPress theme should have the styles and images for just the BuddyPress parts.
You could of course still provide the two themes in one download package, but they should still work independently. It’s not a good idea at all to make the themes dependent on one another. Someone may want to use your member theme but keep their own blog theme.
I’ll be writing more docs on this soon.