The 1st Amendment bans government from “abridging the freedom of speech”.
It does not apply to individuals seeking to talk over you or shut you up.
Charging these disruptors with trespassing at a private event seems to be the only legal recourse.
Ugh, no. Verbal/physical assault on those near them in the crowd, depending or both. Failure to immediately obey the police by not leaving is failure to obey a lawful request and they can add assault on an officer of they physically resist. Oh, tack on disturbing the police.