Your clan might be one of the few who manage to do them all. Hopefully the devs will share the numbers after the event ends!
The bit you said about everyone being able to feel like they are contributing is key here. Clan challenges require everyone to chip in, but some of these challenges are simply not possible for all players. This risks people feeling like they are letting their team down, and others feeling resentful they're missing out on rewards due to other people. You wouldn't want it to be too easy, but if the challenged were designed around each clan having say 10-15 active a high-end players, that could provide enough flexibility to allow a wider range of clans to participate. Let the well-oiled clans tear through it in a couple of days, while the more casual clans still have a chance to complete it after a while.





I suspect there are a few clans where this maybe the case, but there's no real way of knowing.
