I'm not sure Castlevania will be on it or not, but I did see an article regarding SotN and Rondo of Blood just got rated again by a Korean ratings board "seemingly as a collection for PS4".
https://www.ign.com/articles/2018/09...-coming-to-ps4
If this is a seperate release, they may not include it with the PS Classic. Unless they are able to kill 2 birds with 1 stone by getting it rated for multiple releases.