According to page two, panel five of this doujinshi (hosted on e-hantai.com) http://g.e-hentai.org/s/e95d51000b/449333-2 real XXIII's dark skinned muscular girl is called Rafaela. I know it may not be the same person, but it's hard to mistake her looks for someone else.
I still wonder what his blond_ahodge_girl is called though...
I don't know about this artist's works, but I'll assume that they are the same person for now. Even then, the name ラファエラ could be either Rafaela, Raffaela or Raphaela.
The similarity could be simply because he likes drawing dark-skinned blondes. This Rafaela looks like a one-shot h-manga character, while real_xxiii's_dark_skinned_girl is always shown having a special relationship with real_xxiii's_ahoge_girl (first depicted as lovers, then as a married couple wearing wedding bands, and occassionaly each other's jewellery).
Better wait until the artist gives some info about their names on pixiv before aliasing anything.