I don’t think all players are going after that specific RP, they’ll be involved in the final war but not all are going after the one piece necessarily. For example Shanks might already have it and he and BB could fight for it, Dragon and the revs are not going for it but will take advantage of the HKs involvement in elbaf to attack the WG etc
Right now, the threat isn’t really there. Shamrock, Gunko and one other are a problem, but they are not a catastrophic one. The Strawhats, the giants and Gaban can deal with that. Maybe won’t be easy, but it’s not a big deal.
Loki’s a wildcard, but he’s also just been beaten within an inch of his life. He will have a massive role, but he’ll need time to recover for it. And while he’s probably going to fight Luffy with the build up, I am with people thinking he’s not so villainous as he’s painted. So I’m not sure he’s final fight of the arc (although his strength has been built up to be worth that).
There’s got to be some wild changes coming to Elbaf for it to be suitable as the penultimate step before Luffy becoming PK, which is basically what Gaban having the final RP means. There’s an entire untouched area, Usopp has done absolutely nothing, Kidd’s got to play some part. I’d find it strange if no one put of the main players actually comes to Elbaf at this step.
And of course, Luffy should be meeting Shanks soon, and I’d say before he becomes PK makes the most sense. Shanks has a load of links to Elbaf (and Yassop and Usopp are a connection as well). Will they come back?