Host same application with different design
Only if there are already tons of apps that will let you navigate, say, The Smithsonian Museum of Natural History."  Then that one app for the smithsonian MAY be rejected.

But, I suspect there are not, so you should be fine.

Similarly, since you'll presumably be adding additional apps with different functionality, say the next one is for the Guggenheim, you should be fine.  The 2 apps couldn't possibly be used as a replacement for each other.

Apple's concern here is keeping out over-served functionality.  There are so many "fart" apps that yet-another-one can't possibly help any user anywhere beyond what's already available.  Museum apps are well outside of that scope, assuming you create a quality app with a great UI for museums that don't already have several hundred apps.