Aint Hancock going to see Ace, As the orignal plan was for Luffy to stay in Hancocks coat, but with the body search she's going ahead? I'm thinking on the journey to lv.5 Luffy will make a little gang of people he know's. Buggy, Mr.2 and mr.3, mr.1, crocodile, Arlong if he is there(Hatchan said they are still in prison, we dont know if that is impel down or a regular prison), Jimbei(maybe he tells Luffy he doesnt want to go to war as they stand no chance against whitebeard and would rather revolt against the government with Whitebeard). I think once they get to level 5, hancock will already be there with the vice-warden guy and Garp, and Hancock will turn them to stone, but Garp counters it and isnt effected cause of Haki. Luffy will fight him using Haki.
Now, we never see a training scene in OP. with the gears, Luffy figured them out during Water 7, and revealed them in EL. I think the same will happen with Haki, a flashback will show Hacock telling him the basics, it makes you stronger, faster, predict movement. and Luffy will use that, but Garp is still stronger, Luffy uses Gear 2 along with it and knocks Garp out, the others take out the vice warden and VA, and they free Ace, but when they get to the top of ID, maybe one of the admiral's is there.
so i'm predicting all the baroque guys there(1,2,3, croc), buggy, jimbei, ace(but dying), Arlong if he is being held there, and luffy and hancock make it out,