For me with BTS- V was the youngest, RM was the oldest, Taehyung was pronounced like Tiehyung
Blackpink-Rose was pronounced as a rose(the plant), Jisoo was pronounced like JisOO(like how you normally say the letter O), Jennie was not really nice(I believed this because of those toxic people who said that Jennie was mean and I believed it until I started to watch more content)
Aespa-Karina insulted Kai, BTS and others ( because of the stupid articles that came out)
ITZY- Ryujin was the leader ( I thought this because when I searched her up I say a picture of her holding a mic) Lia was the youngest
Exo- Exo had 11 members ( Heard they had a lot of members)
Seventeen- Seventeen had seventeen members
Shinee/WAYV- Lucas and Min-ho were the same people
Edit: BTS's actual debut stage was at Billboard because of Ellen