My name is
Heidi and we considered using
Adeline or
Adelina for the very connection you mentioned. I think they sound pretty together (as a sibset), but it's not a pattern I would personally choose for my children. I would be more likely to use
Heidi and
Adele.
As for the name itself... it's catching on in popularity because of the popular Ad-sound. It's a grounded name, and gives off feminine frill without being over-the-top (think Ameliana and
Alexandrina, etc). I do like the nickname
Addie, but feel it's a bit over done and would personally call her
Dell or
Ada.
I happen to really like the name, but if your husband doesn't like it, I don't see it making it to the top of a real baby name list since agreement is key in naming kids. Outside of naming a child though - Its a beautiful name.