I like both combos but have you ever thought about
Charlotte Maria?? Out of the two up there I prefer
Evelyn Maria. I think they do sound too similar and might not be best for sibblings (and this is coming from me being the one who wants to name my kids
Jack &
Jake lol). I like two middle names but I think it's going to depend on the sound of it and if it flows nicely. Both those combos with 2 middle names I think are really lovely.
Some ideas from the names you like:
Natalia Anabel
Anabel
SofiaImogen is a really nice name and I think there's not enough
Imogen's out there.
Imogen Anabel
LavenderImogen LavenderImogen Leonie (another nice name not used enough!)
I hope I've been some help =)