Well Trevor does not look all that different from classic Trevor. I'd say he looks identical to kojima's Trevor, just slightly broodier. and green.
Alucard is the big departure, but even then he's not that different in overall design. White hair is no stranger to Alucard, and he has similar black/gold colors to SoTN. He does look more Belmont-ish though, but overall, his design is believable for Alucard.
I liked Kojima's Simon, and classic simon, so thats why i didnt mind the fusion, i always liked redhead Simon best, because it's just unique. There's no other redheaded Belmont. Meanwhile, theres a Blonde or two in the family. Blonde and brown are the common Belmont hair colors. (Juste has white, which makes him stand out)