Yamato is too connected to the samurais to get a bounty. I still don't believe that she'll join the crew. The fact that GB didn't even knew her (after looking at bounties of the crew) make it more so. All in all I'm betting the crew is complete with Jinbe with 10% chances of either Tama or Caribou (being very generous) and 1% chance of Yamato (again being very generous). But they sure will milk it a lot, so I doubt that next chapter will deal with her. They will hint and end in a cliffhanger before the break.