I'm going to apologise in advance if this is too generic, or too cultural studies/fashion history for Ask Historians!
By 'subculture' I mean a group of people who share the same non-conforming fashions, ideals and behaviours, who are identifiable through shared symbolism eg punks.
I recently read Dick Hebdige's Subculture:The Meaning of Style, and only post-war subcultures are mentioned, with a mention of 'zoot-suiters' being the first real subculture.
Is there any evidence of earlier subcultures ? Surely throughout history there must have been groups of alternative people, who shared symbolism to identify themselves as belonging to a non-conforming group?
If there was any early subcultures, what was the mainstream reaction to them? Was there the same 'moral panic' as seen with the mods vs rockers?
To answer your question: No.
There are many many examples in the ancient world of "cults," oriented around specific gods/goddesses but also sometimes heroes or even real people believed to be divine. By your definition, many of these cults qualified as "subcultures" since they included ideals, behaviours and fashions that were non normative, albeit for a religious purposes.
Similarly, during the medieval Europe a great many subcultures arose in the form of religious orders. For example, Dominican friars had different fashion, ideals and behaviours than Franciscan friars, even if they were all European Catholics.
As for moral panics, it's very hard to say because you don't clearly define exactly what qualifies as a 'moral panic' as opposed to a religious or cultural conflict.