You can walk around with a beer in Epcot if it is in a plastic cup and not a glass container. The Rose & Crown pub and the kiosks and counter service restaurants will provide plastic cups.
I am sure you can get beer at the kiosk outside the Rose & Crown, inside the pub to drink there or carry out (I like to carry one out and see the World Showcase Players or the British Invasion), and at stands in Canada, Germany and Norway. There are probably kiosks and counter service restaurants in other pavilions that will serve beer.