They'll probably get lumped together in the same room for the first few years, since our house is fairly small and we need to keep a guest room/computer room for a while. And since Alexander outgrew so many of his outfits so fast he barely had a chance to use them, she'll no doubt inherit a bunch.
As for ultrasounds.. true! If they get a good look at the genitalia, they're still only about 95% sure! So either we're having a girl, or we'll have a very peculiar boy with female genitalia. :p