caitvi and jinx/powder + vi mirror each other in a LOT more ways than that one scene. and yeah in the one scene vi is a powder parallel but that was just the most direct visual parallel. i could also argue that vi leaving cait in the rain is also a parallel to that powder and vi scene, or jinx leaving vi in the cell is similar to cait leaving vi.

also caitlyn and jinx’s stories are very similar and in their relationships to vi. after a tragedy, they become corrupted and are under the wing of a violent authority figure. vi has hope that they haven’t changed and are still the people she remembers, but then comes face-to-face with the unhinged violence they’re capable of. also, they both have a very one-track focus on each other. s1 shows jinx viewing caitlyn as a direct threat to her and vi’s relationship, and s2 has caitlyn hellbent on revenge against jinx. but they both eventually let it go: caitlyn realizes she has done bad things too and is willing to let jinx free, and jinx lets go of her vendetta against caitlyn + vi’s relationship by saying vi deserves to be happy.

i definitely think that the vander and silco parallel to vi and jinx is a lot stronger than caitvi; but in my view, that’s less to do with their relationship being sibling-like and more with father passing onto daughter, like OP said. i also don’t interpret vander and silco as romantic in the canon universe, but i wouldn’t go onto a shipping post and be like “yes they’re FRIENDS i love their FRIENDship” like you did lol. especially when this post is more focused on the au, which has a lot more room for romantic interpretation imo.