So much speculation about Orochimaru and Sage Mode. I don't really think that Orochimaru can use Sage Mode, even with Zetsu's body. Judging from Naruto's training, Sage Mode isn't based on one's body, but rather their ability to harmonize with and control natural energy. I don't think Orochimaru's mentality would allow him to properly control natural energy. Plus, every body he has ever taken over has eventually rejected him, and Zetsu is just a knock off copy of Hashirama. These also would probably play to Orochimaru not being able to achieve Sage Mode.
As for Sakura. Who knows? Maybe she's had a slug attached to her body since the Pain Invasion Arc, and has been slowly gathering natural energy. All she needs is for the slug to gather enough, and then we will get to see Slug Sage Mode. At this point, I don't think anything Kishi could come up with would surprise me. Sakura, the slug, and Slug Sage Mode might not make sense, but it wouldn't be a surprise.
