What is "legit" foreshadowing? It is foreshadowing, but it's more or less a no brainer for some of the fights with the manga going into a direction of BB pirates vs. Strawhats. Also Luffy having a feud somewhat with Akainu after he killed Ace is not in the least bit new.
Is it? I always thought they just put some dream matchups that would look cool for an exciting opening.
openings usually feature matchups that will happen with the next few seasons and serve as a teaser to anime only fans
however these matchups dont even seem remotely close to happening in the manga
unless they will take place consecutively after dressrosa