How will numerous nation groups present unified ‘representations’?
As the Principles state, the Voice itself will have a wide range of representatives from all around the nation. It will also develop methods of consulting with local and regional communities.
Whether or not people's opinions need to be the same depends on the issue. Some things may only affect a certain group of people or a certain local or regional area. When it comes to things that affect many communities, the Voice, the government, and Parliament may need to accept that policies need to change depending on the situation on the ground.