Potential outcomes from the Reverie:
1. The "publicized" death was Sabo. The actual death was Cobra. This is the only logical explanation for why Dadan/Makino reacted the way they did. My guess here is while Sabo and his commanders were fighting the Admirals over Kuma, Kuma decided to escape using his power. Sabo grabbed onto Kuma when this happened. Currently Sabo is "captured" at Vegapunk's facility, but reported dead to bait the Revolutionaries.
2. The attempted assassination was Vivi. However, the assassination was merely a cover for the WG trying to capture and "erase" her, essentially bring her to Im. Because it failed, the WG wanted to cover it up, Morgans didn't allow it.
3. The Shichibukai System was Abolished. Obvious
4. The news Wapol leaked was Pluton's location and has to do with Cobra's death (Wapol hated Cobra, so its very possible he snuck around listening to Cobra/Gorosei's conversations). Vivi is possibly central to this or something else. Cobra leaked the location before he died (it was never indicated he DIDN'T know about Pluton and its location). This is what Blackbeard/Marines are fighting over currently.
Leo is currently back at DR according to the last cover story but we have no idea where Sai is. Its possible Sai ended up protecting/saving Vivi from being taken.