I don't know about Trails End specifically, but all the buffets on property we've been to include any of their fruit juices, coffee, milk, soft drinks, or of course water.
They have "real" sweet tea at Trails End? I didn't know that!! I didn't realize it was available anywhere on Disney property.
We have reservations there for both breakfast and dinner in May so I'll definitely have to check it out. Does the Hoop-Dee-Doo have the same tea since they share a kitchen? We also have an ADR for the HDDR so this could be really important info!!!