My cousins name is
Annabelle Catherine, so I am a bit biased when it comes to spelling. I prefer that one myself-
Annabel looks incomplete to me, but that's probably just because I'm so used to
Annabelle. I think it's a lovely name, either spelling. Great nn potential too- my cousin mainly goes by Belles, but she gets
Annie a fair bit too.
I like
Amabel, but prefer Annabel(le), because I do think it would often be mistaken for Annabel(le) and because you lose the potenntial nn
Annie, which is one of my favourite things about the name. I prn. it same way as you do.