The hotkeys switch between states so you can use this to make an "avatar mute button."
Just create another state and use your closed mouth file in your open mouth slot and closed mouth blinking file in your open mouth blinking slot. Then set your mute hotkey in OBS to the same hotkey as the new, unmoving state, and set your unmute hotkey in OBS to the same hotkey as the moving state. And you're all set!
Hope this helps someone. I know this is old but just wanted to drop this here in case someone else finds themselves in this old thread looking for a solution.