of course i think they could. but there's just so many variables involved with this. I've never done a gathering but i assume there's going to be up to 20 climbers(which we all agree is lot on what could be unstable conditions), plus it's Mother's Day weekend. Just seems like a viable option to push it back and take care of some of these variables.
It might be a good idea to split the gatherings into at least 2 destinations and/or dates. Sounds like a lot of people anyway. Just a thought. Two gatherings would spread it out a little. I agree that 20 climbers is too many for Castle/Conundrum (but is still great for a bit smaller group).
Crowds are fun for socializing and stuff, but for couloir climbs and for ones that required above-average skills, a big crowd might not be a good idea.