I like
Serafina. I think
Seraphina has had some attention since it's a celebrity baby name and
Serafina has been forgotten about. I find it less OTT and princessy than
Seraphina.
There is also a character in
Looking for Alibrandi named
Serafina "
Sera". That was where I first encountered the name.
I would rather see
Serafina than
Dante, on either gender.
I think
Serafina goes well with
Arthur but not
Keiran.
Keiran I get a completely different vibe from. I also grew up with a bunch of Keirans so I don't see it as being as exotic or intriguing as
Serafina and to some extent
Arthur.
Keira on the other hand goes quite nicely with
Serafina.
I think you can get away with using
Serafina without the particular ethnic background.
And I like
Sera for a nickname, and then
Fina. :)