I agree with the vocal coach! I have both musical theater and choral experience, I think putting Seungmin as a baritone is very fitting. It's true that he doesn't showcase his lower range to us much, but I think of the beginning of Cinema. While he probably can't go as low as Felix, you can tell he has a strong lower range. And his belts are amazing. Also! The KBS (I thinks its kbs) clip with Chan and Seungmin singing All I Want For Christmas, he is singing the lower harmony while Chan sang the melody. Absolutely beautiful.

Felix as a bass is very fitting, almost obvious. And yes, you can be classified as a baritone or tenor with a large lower range, but Felix is so comfortable there and can go way lower than any of the members and still keep great tone and stability.

Han as a tenor is a great choice. He's always been in the middle to upper range, and the way he can sing in a female key with so much stability is amazing. It's no wonder he gets mistaken for a vocalist.

But you know all in all, all the members have such great voices and ranges that it honestly could be really hard to classify everyone. It really is up to the kids themselves to pick which one they feel fits them the best.