I just don't see the marines sending out an admiral this time, only Sentoumaru and the pacifistas, and I think the crew can very well decimate them. The pacifistas may have performed well against new world cannon fodder but Hancock was lopping of heads left and right. Luffy or Zoro could effortlessly dispatch pacifistas of that level. Of course, the new versions are likely stronger but I dont think it would be a problem. That being said, I doubt theres going to be a big fight, more like the strawhats proving a point and then making a run for it.
Also, theres no reason in having a showdown between the fake crew and the strawhats at this point. Luffy can wipe them out with a single stare,