I really wanted to call dd2 Elizabeth, but couldn't because my BIL called his dd Elizabeth (dh's brother so they have the same surname as us). so I ended up using Isabella instead.
In the end BIL and his wife got divorced, they live in a different country to us (and we NEVER see them) and they always call their daughter Libby. I still like Elizabeth (Eliza for short I think), but know that Isabella is the spanish form of Elizabeth. Would it be too much using the 2 names for 2 sisters? - there are 9 years in between the 2 of them if that's relevant.