Raphael is definitely not too unusual in Australia. I know a Nicholas and Raphael who are half brothers. It’s a very nice name, highly international, and Rapha /Rafa or Rafe are cool short forms. I like the reverse symmetry with the brothers’ names and think they match.
I haven’t read your previous posts. Have you put the paperwork in? I’m not sure changing the name to something other than Leo is a good idea when you feel Leo is so perfect. Try to keep communicating your feelings to your husband in a way that shows you value him and his support.
I like the suggestions of Oscar, Felix, Eli, Sam and Milo or Miles, but would suggest thinking about meaning for you to see if there’s anything you connect with more than Leo. Is there a particular European country or countries you have ties to? Vincent (Vince)? Or Victor (Vic)? Adam defines timeless…