I will just add that a constitution is not a treaty and te tiriti can't just be 'assimilated' - its a founding document unto itself.
That is, its original form is not lost or changed (as how it has been & Seymour and others are trying to do) and from there a constitution is drawn up to address the rights of all people/ New Zealand.
Much of what you said has been happening already (except the constitution part) with local authorities across the country working to initiate co-governance contracts with Maori and communities, land ownership issues through the Waitangi Tribunal, Maori Land Court, through council consent processes (where they're not snuck through unnotified) especially for water issues and waahi tapu through Hertitage NZ and Archaeological expertise, and more besides. Its been a slow arduous process but gains have been made where all sides have reached consensus. And those gains are a large part of what will be affected through the 100day action list & the oiling of the squeaky wheels of those that have monetary/ pecuniary interest in seeing repeal of environmental, health & wellbeing, and Maori self-determination reforms, or just plain bias.
A constitution drafted outside of politics would go a long way to bringing everyone onto the same page but it cannot relegate the original treaty to a clause somewhere just because Maori are 'outnumbered' today.