2. Charcoal canister is an EPA smog remedy. Charcoal canister absorbs gasoline fumes from fuel tank rather than venting the fumes to the atmosphere.
In turn, when you start the engine, the fumes are drawn from the canister into the intake stream, burning the fumes during combustion.
Missing charcoal canister is only a problem if you have to pass smog inspection. Otherwise, a missing canister won't affect engine performance, unless it wasn't removed properly.
Replacement canisters are available but most parts stores don't stock them. So, they'll have to order one for you. (There shouldn't be any charge for ordering one.)
