Where is the guest drop-off/pick-up area located? Do you get there through the general Epcot toll plaza?

Yes you have to go thru the main gate.... Most of the time you dont have to pay i think it depends on how busy they are. Once you go thru the main gate the parking lot people will guide you to the drop off pick up. But there is only one way in and thats the main gate.

There should be no charge if you explain at the entrance that you're going to be dropped off, for Epcot the entrance for guest drop is to the far right - after you speak with the attendant at the entrance plan to start to merge toward the right

Yes,, stay to the right and yo6will see signs where to go