On joining the minyan and a public messenger

Hello Rabbi.
As you know, there are many who think that anyone who holds opinions like the Rabbi’s is a heretic (of course I have no problem with that), I agree and think like the Rabbi on most things.
A. Is there a halachic criterion related to joining the minyan or becoming a public servant that I fall into? (According to them, the rest of the world).
on. Do I have a moral obligation to say this if it is obvious to people that I am part of the minyan and they even ask me to become a cantor?
thanks.