Chapters: 552 - 562 (Yes, 11 chapters because they are all 17 pages; this is thus less pages than 10 19 page chapters)
Color: Light Blue
Title: "Justice Will Prevail!!"
Characters: Whitebeard, Marco, Jozu, Oars Jr., other Whitebeard pirates…I'm hoping for 57 being the WB Pirates and then 58 being the Marines and Shichibukai...sort of like the 21/22 (Baroque Works vs. Staw Hats) covers or the 42/43 (CP9 vs. Straw Hats) covers. Aaaactually it seems Oda goes in reverse order, at least in the two instances in the past...so perhaps vol. 57 will be the Marines (Sengoku, Akainu, Kizaru, Aokiji, Garp, Smoker) and the Shichibukai (Mihawk, Hancock, Moria, Kuma, Doflamingo) in a big spread then 58 will be the WB Pirates...both sort of have the spotlight in 57 but thus far in the vol. 58 chapters, Whitebeard has finally been making a move. So perhaps 58 will have Whitebeard, Oars Jr., Marco, Jozu, Luffy and perhaps Croc, Jimbei, Buggy, and Ivanokov again....I don't mind which order, but I'd love to see those two covers XD
Alright after that rambling paragraph, my ACTUAL prediction for the characters on this volume cover - Sengoku, Aokiji, Kizaru, Akainu, Garp, Hancock, Kuma, Mihawk, Doflamingo, Moria; other possibilities - Momonga, Smoker, Tashigi, Koby, etc.
As for the chapter number issue, I'd say there's no way it'll end on 560 if Oda was so concerned about not charging fans extra and wanted to include 11 chapters as a bonus. If he does 9 chapters when only doing 17 page chapters, that's about 37 pages less than what he normally does...11 chapters at 17 pages per chapter is closer to the actual page number of a 10 chapter, 19 pages per chapter, volume.
561 is not a good cliffhanger, so I see the reasoning behind the ending being 560, however, that leaves only 153 pages of manga...even with SBS and extras that's like 160 - 165 max...no way Oda will put out a volume that short.
11 chapters brings us up to 199 pages. I'd say he'll do 12 this volume before he does 9 for that matter...12 chapters would be 216 vs. 165...I think he'd go for the little bit of extra money over putting out a volume that will cost as much as a 10 chapter volume when in fact is much shorter.
So yeah, I think it'll be 11 chapters. That SBS was from volume 53, way back in March. I'd say he more than likely did not plan to switch over to 17 page chapters so far in advance. Price of volumes should be determined by page count, not by chapter number.