1. Sanji doesn't know Yamato, or her strength. Enemy broadcast is calling Yamato, young master. Without any intel, one would assume he's chasing Momo and Shinobu, both fodders. Scabbards would hang their heads in shame if something were to happen to Momo, Sanji knows that quite well too.
Yamato has met Ace's brother, Her idol's son and now it's time for her to meet "his" (Oden's) sheaths and protect them. There is little to no reason to not go to Momo, from logical perspective from intel Sanji has, Momo needs more help (a question raised this chapter), and that's what Scabbards would've wanted too.
2. Perospero sees Marco, and only him this chapter. He sees he's getting worked up. And if we go by their last interaction, Peros is not helping Marco. He LITERALLY says he needs to teach these upstarts, what an Emperor is. Why help the same upstart force keeping all these things in check? Would make no sense.
3. Apoo and even Hawkins will switch sides soon. I'm more interested in seeing how Hawkins changes his side. Apoo probably is already pissed and disrespected enough, a little glimmer of hope and he's dropping the bass on Queen. At least once.
4. Cliffhanger leading to death? Can only happen in Two Piece. "I'll be surprised if he actually dies", should be the default reaction of everyone. Man's a beast tho.