I think it is important to have two separate days, because they do not have the same purpose and they are not designed in the same spirit at all.
You mentioned a lot of things, but I think it ultimately takes two separate days, and each day has to have a completely different goal. I have always considered National Indigenous Peoples Day to be a day of recognition, as set out in the Constitution of Canada, the recognition that Canada's indigenous peoples have a special place in this country. Indigenous people are specifically mentioned, just like English and French.
National Indigenous Peoples Day has always reflected this recognition, but what we are proposing is to recognize, first, a big secret, as our society experienced it until very recently.