AS to whether they were considered heretics, what do you think Augie thought of them? Surely he thought they were in error. I'd guess they couldn't really rise to the level of obstinacy required for heresy until there was an authoritative statement to the effect of, "Yo! Y'all are WRONG! Chill!"
Everything.
Prior to the power of the state being used to enforce the will of a hierarchy churches choose to cooperate or not. Now they would no longer have that option. While the mono-bishophoric system began to emerge in the 120-130 AD it still did not have any power to force cooperation. For example Clement writes a letter complaining that the church in Corinth has changed their leadership. Other than sending a letter he had no power to deny the church in Corinth the right to do this.