I'm thinking 1089 - 1098 with the title being Luffy vs. Kizaru.
The cover will have Gear 5 Luffy on the left and Kizaru on the right, both facing each other in fighting poses (either Kizaru summoning his sword or doing his Yatagami attack while Luffy is legs spinning arm up ready to punch Kizaru). Behind them in the background will be Saturn's face, either in regular of hybrid form. You'll only be able to see his face. Then at the bottom it could go either way. We could get it dedicated to Kuma because the flashback starts here but Oda could also save 109 to be a cover dedicated to Kuma and Bonney, as it will have 1099+ which is still all the Kuma flashback.
If this cover does reference Kuma, then he'll be in the bottom centre in his priest outfit. Ginny and Ivankov will definitely also be there, with Dragon and Gyogyo as other options if Oda needs to fill space. He'll save Kuma and Bonney being together until the next volume.
If the cover doesn't reference Kuma then it will be the Vegatank in the bottom instead, with Vegapunk, Atlas, Franky and Sanji all being in it or holding onto it.