While the debate over who is Métis rages, one thing to remember is that Métis ancestry doesn't rely on some far distant ancestor. Rather, it is tied to an ancestral connection to the historic Métis Nation that arose in the Metis Nation Homeland which includes Manitoba, Saskatchewan, Alberta, parts of Ontario and the Northwest Territories, and portions of northwestern Minnesota and northern North Dakota and Montana in the United States. Just having evidence of an Indian or aboriginal ancestor is not sufficient proof that an applicant is Métis, and without evidence of a connection to a Métis ancestor, a person simply lacks proof that would allow them to qualify for anything beyond self-identification.
For instance, you can find evidence of Métis ancestry and a connection to the homeland by finding your ancestor's "scrip", awarded by the federal government to the Métis inhabitants of Manitoba and the former North-West Territories. Such scrip records are readily available online HERE. I am personally fortunate that several of my ancestors had applied for and had scrip issued.
As an example, here is my great great grandfather's scrip, issued under the Northwest Scrip Commission:
His scrip lists where he was currently living (Walhalla, North Dakota), where he was born (Cypress Hills, Saskatchewan), and outlines his claim to scrip based on where he lived prior to 1870 and established that he was a Métis based on his parents being "half-breeds" living in the homeland.
His father also received scrip under the Northwest Commission, and his scrip document further lists his children:
Other ancestors of mine also received scrip under the Manitoba Scrip Commission (click images to enlarge):
In addition to these Canadian scrip records, which demonstrate provable genealogical connection to the Métis Nation and the Métis Nation Homelands, other forms of information can be used to prove a connection to the Métis Nation. For instance, here are two issuances of Half-Breed Scrip, granted to my 3rd great grandfather and 4th great grandfather, under the 1863 Treaty at the Old Crossing in the United States, whereby Métis members of the band could obtain scrip and land under the treaty:
Both of these individuals also had received Canadian Métis scrip (as shown above) which was not uncommon since the Métis people were quite fluid across the borders and many received scrip under both authorities.
Another source that can be used to prove Métis ancestry are the 1870 Red River Census indexes. These indexes show families who were part of the 1870 census and these indexes list if a family is Métis and usually list all family members. For instance, here is one of my 3rd great grandfather's indexes. It shows my 3rd great grandmother and my great great grandfather as a child:
Other censuses, such as the 1901 census of Canada, show people as Métis in Manitoba and Saskatchewan, and various other records can be used as well. However, the main focus of all of these is towards proving Métis ancestry and a connection to the Métis Nation Homeland.
Once your family tree is completed, you can always apply to the St. Boniface Centre du Patrimonie to have a certified "proof of Métis ancestry" completed. This proof will establish and certify that a person truly is associated genealogically as a Métis person. The proof is that the applicant has an ancestor that has been identified as Métis through official documentation such as census records (1870, 1901, 1911), scrip or land grant documents (including the affidavit or the index, etc.), or other official documents such as church records (parish registers or other).