You're saying that a band can only fit in a genre if they have all the stereotypical elements that define that genre and that playing it a little different (By adding a trumpet fart or something) makes it prog, experimental or avant garde? Typical. That's the problem these days with genre categorisations imo. Words such as 'progressive' 'post' and 'avant garde' gets too much abused if you ask me.
It's not metalcore if it doesn't fit the stereotype, . Then it gets prefixes like 'progressive', 'avant-garde' or 'experimental'. The 'metalcore' suffix depends on the bands said band lists as the ones they were inspired by.
Rest in peace Ronnie!!!
Past The Point Of No Return - Phantom Of The Opera.