Akainu doesnt need to be controlled at all for that to happen lol. Guaranteed he'll be present when the Yonko start fighting each other over the 4th Road Poneglyph, possibly at or around Lodestar.
Logically I think Elbaf will end with Shamrock coming back and him and a set GKs losing to Luffy's group, while the rest fall to Dragon. It makes sense given the unfinished business he has with Loki and the fact that Elbaf Giants are convinced Shanks cut them down with Luffy acting concerned. These scenes have no meaning this arc of they dont pay off and the Giants realise it wasnt Shanks that harmed them.
With this im convinced he comes back and is dealt with here.
Then when the Yonko start clashing (i.e. Shanks vs Blackbeard), its the perfect time for Luffy to fight Akainu and his Admirals because this is what gets implied several times about how the Marines (i.e. Koby, Ryokugyuu, etc) have stakes in stopping Luffy or Shanks from getting One Piece.
After that its obviously Blackbeard (One Piece) and Imu (the World). Oda has been moderately straight forward with his progression and IMO this is how the endgame will be structured because Oda has yet to actually deviate from his arc and escalation structure. Even though Egghead ended unorthodox, it still ended with Kizaru and Saturn fighting Luffy and "losing", however you want to frame it.
Tldr:
- Shamrock at Elbaf
- Akainu at Lodestar
- Blackbeard at Laugh tale
- Imu in the Final War
Is how i see it now.