Caroline Dries teases a “rich and heartbreaking story” for Stefan in season 5

From Gime Me My Remote:

How soon will people start to piece together that Silas is pretending to be Stefan?
CD: I won’t tell you how, but I will say our characters are very smart and they have a lot of resources as their disposal. So one by one they figure it out. But it’s in an order that is kind of detrimental to some of the main characters. It’s not like it’s a season-long arc that he’s going to keep this secret, it’ll be fairly soon.

We’ve talked about Silas as Stefan, but not Stefan himself. Will we be seeing a lot of him while he’s trapped, or is his screen time going to go by the wayside until he’s able to get free since there’s a limit to what he can do down there?
CD: [Jokingly] What are you talking about? He can sing “99 Bottles of Beer on the Wall”! He can do little twists and turns [in the container].
Believe it or not, Stefan does have a story — we got comments that no one talked about Stefan at Comic-Con; Stefan has a really, really rich story in the premiere that I’m actually super excited about. And it’s beautiful and probably very difficult to speak about without spoiling everything. But I will tell you he suffers and his stories are heartbreaking, but we get to see a big story with him.