I'd say they'll be legislated back to work by February at the latest. The rural economy will be impacted greatly, and action will be needed.
Canada Post seems to be racing against the clock when it comes to getting a deal reached. Not only for the holiday season, but for the life of the company. They made tiny movement in the talks recently, but that's normal early in a strike. If the mediator keeps facilitating the talks, they may be able to save the holiday season, otherwise they may end up getting a deal reached when the low-demand period starts in January.
Unions tend to pick a peak period for going on strike. If that tactic fails, they end up settling early in a period when demand would start to decline. Happens in most strikes - especially transit strikes (which are usually settled by early February - when ridership is low, as hardly anyone wants to stand at a bus stop in bitter cold temperatures), and the 2023 Federal Public Service strike in which they chose tax season - the peak period - to walk off the job, and that deal was reached after that peak period ended.
Canada Post is under panic mode now, and they are fearing for the company's life. They were on track of depleting their operating capital by early 2025 (and the strike might cause them to deplete their operating capital much sooner).
I think, when the strike is settled, they will likely settle on a 16 or 17% pay hike over four years, but in order to pay the workers that much money jobs will have to be cut. I wouldn't be shocked if any job cuts happen, it will probably be announced in next year's federal budget - and the job cuts will be in the form of closing down post offices (and selling them) and consolidating them into bigger post offices, and even setting up postal centres inside convenience stores, additional drug stores, and even supermarkets. I wouldn't be shocked if postal outlets may end up being set up in Loblaws-owned supermarkets.
As far as I know, talks haven't broken off - otherwise I would have noticed by now.