Yes, the choice button doesn't show up on the header in Epic.
Try changing to another one and then when you go back to Epic if that's what you prefer to use, then it'll still show there underneath your username and avatar. Give that a try and let us know if it works.

Edited later to add:
I had to go for a while. I've just come back and tested it in Epic. I still can't find where you can actually set your Mood in Epic, but as I said, if you set the mood with the option in one of the other themes, e.g. chestnut or default, then when you change back to Epic, the moods will all show up just fine.