How do I release the tab holding the fuel vapor canister in place under the vehicle?

You just squeeze the connector oblong, so it releases from the canister, here are the instructions in the images below. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.

So, I disconnect the hoses then how do I remove the canister? Can this all be done without dropping the fuel tank?

It looks like you might need to drop the fuel tank. Here is how in the images below. Check out the images (below). Please let us know what happens.