Charcoal cannister

If you are changing the carb I suspect you live in an area that you do not have to smog you car or get "safety" checks.

If that is the case you can most likely cap off the lines unless they provide the breather for the tank.

The PVC runs off of manifold vacuum and as such makes a controlled intake manifold leak that the carb tuning accounts for.

The charcoal canister if "Yed" into that line MIGHT introduce another manifold leak that maybe the carb can not be adjusted for.