Yes, I will confirm that as I asked on our way out when we were there a week or so ago. We had 10:20 ADRs and left around 11:30-11:35 and people were still waiting to sit then and there was plenty of food up at the buffet at that time.
The CM's told me even though their last seating is at 11:20, people may still wait to sit, so the characters are usually still there at least until 12:30ish (sometimes later), they make sure everyone is seen. I'm sure they keep the food stocked until then as well.