Anyone can help me to remember who was the seme and the uke?

Seme is the dark haired one. Uke is the blonde. If that's what you were asking g

yes! ty so much

yup, I think they will stay like that. Although the boss (dark haired) was very open to discussing positions, it's more a preference expressed by Wonyoung (blondie) - I really like that this choice was made intentionally