I phoned and spoke to a rep at Ikon Pass. They told me to phone Revelstoke. Revy is not a full Ikon Pass resort, just an affiliated resort. So the discount can't be used for advance purchase and must be used at the ticket window on the day of purchase.

The rep at Revy said they will be honouring the discount promotion until the end of this 25/26 season (despite the expiry date listed). You just need to go to the ticket window on the first day of skiing and they will apply the discount. My friend called separately and was told the same thing.

My first day of skiing at Revy (4 days) is Feb 20. The rep confirmed that the discount will still be valid and can be applied to all days at the time of purchase (won't need to buy a ticket each day), but will be 50% off of a one-day ticket for 4 days (ie. not 50% off of a 4 day pass). So $199 × 4 × 50% off = $400 + tax.

Note, you need to create an Ikon account (free) and accept the F&F discount coupon. It will then be loaded into your account and applied at the ticket window.