I say go with
Isabella. It's the name you really love, and you will regret not using it.
Don't worry about the popularity. We named our DD
Isabel and everyone told us it was 'so popular' but I haven't met another
Isabel yet, and my DD is almost 20 months old. I have loved the name for years and I love saying and hearing it, and that is all that matters. So go with what your heart tells you, use
Isabella.
Isabella Georgina Fife sounds lovely. :)