Re: Victini; Modeled after Celebi?
A) The V pattern on the belly is the only real shared characteristic that indicates any kind of relationship. Other than that they differ greatly. Victini has large ears, while celebi simply has a big head and no ears at all. Victini has large "legs" with small feet, Celebi has giant feet attached to sticks for legs (There's also the clawed-unclawed difference). Furthermore the remaining similarities are shared by the whole suite of "cute legendaries" of which one is introduced each generation- Mew, Jirachi and Shaymin all also have three claws on each hand, large eyes and a cutesy demeanour. These are simply recurring design trends present in each generation several times (Pidgey>Hoothoot>Tailow>Starly, Ratata>Sentret>Zigzagoon>bidoof, etc).
B) Typing is once again shared with several Pokemon that match the profile; Mew, Jirachi, Shaymin and Manaphy. Two of which also share the psychic typing.
C) Celebi's ability is Natural Recovery in Japanese, whereas Victory Star is a literal translation of the original name. Unless Game Freak planned ahead for this coincidence, it is simply that- a coincidence.
D) Celebi and Victini share very little in the way of connecting backstorys, much less to suggest one is the other's successor. Jirachi and Celebi are a more associable pairing, one embodying time and the other space.
So yeah, I think you're reading way too far into this =P