Required Characters: Astromech, Bounty Hunter, Explosive, High Jump, Protocol, Shortie
Note: This guide may be hard to understand, as I couldn't actually play the level in Free Play, so this is the best I got.
Canister 1 (High Jump): After the first battle with the Emperor, and the area is opened up, head to the middle platform above. Jump up with Boba to grab it.
Canister 2 (Shortie): Under the stairs is a crawl space, use it to get a Canister.
Canister 3: Sitting in the middle of the arena. Easy, so snag it.
Canister 4 (Bounty Hunter): Use the Bounty Hunter Panel in here. Enter the area and head right. Play Chess in here to awaken the pilots. Kill them all for the Canister.
Canister 5 (Bounty Hunter, Explosive): Head left at the crossroads. There's a bit of an obstacle course here, requiring a combination of blasting red canisters to make Grapple Points appear, and using said Grapple Points to reach the Canister at the end of the course. When you see a Grapple Point, a door and a lever. Pull the lever and open the door. Head through to find the Canister at the end.
Canister 6 (Bounty Hunter, Explosive): Sitting behind a Force Field that can be brought down in the course above.
Canister 7 (Bounty Hunter): Sitting on the right, in plain sight.
Canister 8 (Astromech, Bounty Hunter, Protocol): Blast three platforms to reveal two panels, use both the Astromech and Protocol Panel to make the Canister appear over a vat of goo.
Canister 9 (Bounty Hunter, Shortie): Take the Shortie Passage in this room to find a Canister.
Canister 10 (Bounty Hunter, Shortie): From 9, Force the switch to reveal a Canister in the air, back with the three platforms you previously destroyed. (Apparently this Canister CAN disappear if you don't snag it when you come in. So you should probably grab it as quickly as possible.)
Minikit Character: Anakin Force