Hah. Great question.
I'm too young to have a will (and kinda early to have children to be honest), but when I get a bit older (40s?) I'd surely write a will just so if ever an accident happens to me(hopefully not) or if I get like memory problems. and yes, I'd definitely divide it equally between my children.
About the quest:
I'm not sure if I'd like to do this to be honest. I'm not sure if my future children would be willing to do a quest recently after my death. haha. I'd prefer like a year after my death, this can probably be achievable by asking a close friend or relative to do give the quest to my children after a while.
I wouldn't make the quest too hard, but I'd make it short and special like.. have an encrypted text file containing the private key/recovery phrases with a password being like, my 5 favorite places or landmarks on our local city or something. That'll be interesting enough I think.