If we run with this course, then Roxas as always been in Sora's subconscious, and that further confirms an EXTREMELY deep connection between Ven and Sora
No we can however say Ven has been there. Days explained why this might be but i wont spoil it for you.
Also, Ven's presence would be what customized the look of Roxas
There you already knew without playing days why its so.
None of the Nobodies look exactly like their Somebodies
Actually from what weve seen they do.
But its my belief that nobodies have the ability to alter how they look when they go from somebody to nobody.