Does OST and Mixtapes count as Solo debuts? (EXO, BTS, SEVENTEEN)

i dont think that woozi and hoshi's solo releases are solo debuts, seems more like a natural extension of svt's activities in showing each of them individually, plus they have solos in the past too(in concerts etc), so unless it's marketed that way, i dont think it's a solo debut

OST are definitely not solo debut... IMO.

Lily Morrow released 2 OSTs in 2015 when she was 13 years of age, she will be debuting this year as a member of JYPE's next Girl Group.

An OST is an Original Sound Track that promotes the Drama or Film rather than a Debut that Promotes the Artist.

Essentially Mixtapes are what an Individual or group has for their favorites, this does mean that it doesn't have to be their original work AND more importantly, it's something that anyone can do.

Seniority....

For OST's, in Korea, this does count as a debut as far as Seniority goes

Yes, the rap line worked hard on their mixtapes, and they should be acknowledged as the art pieces they are, but no company will consider it a debut. For example, Sza's debut album "CRTL" is not her first body of work. She had a mixtape called S that she later released on streaming platforms. OSTs also don't count. I believe Doja also had a mixtape before she debuted but only her album Amala.

I dont consider so. Especially for osts