Consider joining the Vernon Fish & Game club if not already a member. They sponsor the occasional youth oriented fishing event. Light spinning gear with a small lure like Panther Martin or Mepps has been quite productive for me at a certain Alpine lake I like to frequent. I've been a bit of a die hard fly fisherman for much of my adult life. It's brought success, but having tried the aforementioned spinning lures in recent years I now more often than not leave the fly gear at home. Get each of your kids one of those small pushbutton casting set ups, easy to learn with.
Your kids still very young & I don't think they'll have much success fishing from shore at most of the local lakes. If you don't have a canoe or boat you should consider investing in one. Along with shops already mentioned by others, Canadian Tire has a large section with fishing gear. Unfortunately I think they're still closed as a result of the fire before Xmas. ++++ to Kencraft & Herbie's
OK & Kal Lakes have Kokanee fisheries although the openings for that fluctuate. I have never fished for Kokanee, I think you have to go deep with a trolling set up. There's also opportunity for Salmon in/around Enderby but like the Kokanee, seasonal & subject to closures due to poor runs. Brookies & Rainbows from my favourite lake.