@alfredo said:
Is it legal if both are casting opinions, comments, agreement or opposition to influence the meeting’s agenda in such a way that the son/daughter then vote on an item?
Not sure what you mean by this but they can’t both vote on the same issue and they really shouldn’t both be speaking on the same topic (but that’s an issue that would be covered if you had standing orders for meetings, which you probably don’t). People on committees are allowed to influence agendas – that’s one of the reasons they are there.