Welcome to the busy summer weekends at SGW.
Qu#1 Please cancel or request changes to a permit by going to the “Wilderness Permit” web page and select “Contact” link.
Qu#2 Yes you could tag along with a group of 11 or less if the leader / permit holder is willing to accept the responsible for you as a group participant. Otherwise you could try to summit from another trailhead that does have permits available. (possibly Aspen Grove / Fish Creek)
Hope that helps.