As CBC keeps reporting the Nunavik change, is is it worth contacting their Nunavik bureau in Kuujjuaq? Their contact info (a local Nunavik phone number and email addresses) is on the CBC Montreal website - https://www.cbc.ca/news/canada/montreal/cbc-montreal-contact-list-story-ideas-tips-1.3368463
As for the ungoverned Kenora District, Ontario could issue a regulation in an instant, as long as the changes to the Time Act remain unproclaimed. Individual municipalities (like the City of Kenora) could also do their own thing quickly - though it's unlikely with the municipal elections at the end of October. There's also the Rainy River District (which includes Atikokan and Fort Frances). Though it's more closely related to Ontario and Minnesota than Manitoba. Nothing precludes any of the 50 or so First Nations in those two Districts doing their own thing as well - or the Métis I assume. In particular, the Shoal Lake 40 First Nation, which straddles the border with Manitoba, with I think about 200 people on the Manitoba side, and 100 on the Ontario side. There's contact information on their website. https://shoallake40.ca/contact-us/ The Animakee Wa Zhing 37 First Nation in Ontario is also adjacent to the border. Both of those First Nations have the majority of their membership living off-reserve in Winnipeg.
