hemlockjibber8omp was new last year I believe. Registration wasn't even filled up which was strange. Most of the events get a waiting list. I'm sure it will be insane next year though.
The Jr events are cheaper than FWQ events or old IFSA events. You do still have to pay a reg fee and insurance but I believe it is less than $100 and the comp is usually 2-3 days depending on how many people register and go into qualifiers. The events are always held on inbounds terrain and it is typically mellower and less consequential. They have one venue for ages 7-18 but most features will be closed for the younger kids. It ranges from 7 year olds snow plowing down the guts to 18 year olds throwing 7s and hitting massive cliffs. Full range of talent really.
I agree about something down the fraser valley just for the sake of it being a middle ground. When I used to hold Lord of the Park at Hemlock and Manning, 70-80 people would show up from around the province.
Red, White Water or Kicking Horse would obviously be ideal for terrain, but I think you'd be wise to have it accessible to Whistler & Van.
If LOTP were to be held now the number would be much higher I think. I helped run a U-15 groms slopestyle jam at Seymour last season, and we had easily 90 kids show up, and we had very short notice for it.
The freeride scene is obviously much smaller and more difficult to run than park. Baker would be an ideal location for terrain and hot laps but I would imagine the whole international insurance would be very difficult to get around.