I think Amelia and Amy-Louise are too close. If you want that as the longer version for Millie, I'd suggest the alternate spelling Emilia, as it doesn't look anywhere near as close on paper as Amelia does.
I don't know what country you're in, but I know more just Millie/Millys than I do ones with longer names, so if you're in the UK I think Millie as a given name isn't too out there at all. I did know a girl whose name was Emily and she was meant to be nicknamed Millie but it never stuck. Not one that I would use myself but I think it might work for you.
Hehe it breaks 2 rules 1 being surname and 2 being 2 ms hehe.
lovely name though.
Just wanted to say, Milena is another gorgeous name that you could use to get to Millie. Milena Kitcher? Gorgeous, no?
Also would like to add that Poppy is another name with a similar feel to Millie, if you like that. Poppy would usually be used on its own or as a nn for Penelope, and Penelope and Amy-Louise sound sweet together.
Georgia is a no no as I don't want a kid named after my boyfriends ex girlfriend.
Sophia is too close to Sophie.
Claire on the no no list.
Millie Mae and Millie Kate - see original post.
We don't like unisex names like Ashton and Harper etc.
Millie Hannah - Sounds kinda smushed together.
Millie Annabelle/Isabelle - prefer Isabelle.
Millie Elizabeth - over Eliza.
Millie Jane we like but just not the MJ after Michael Jackson.
All other names he doesn't like although I like Evelyn he doesn't.
Any other names.