Singer/songwriter
Trey Anastasio (formerly of the band Phish) has two children named
Elizabeth and
Isabella. Also hockey star
Ryan Smyth (Colorado Avalanche) also has two children named
Isabella and
Elizabeth.
But to answer your original question - the names are too common for my liking. I appreciate names that are more unique. As for the names having the same origin, I think it's sweet. I happen to love themed sib sets that are not overtly themey. The names are perfectly fine for siblings.