Soundgarden's reunion is confirmed. They are not playing Coachella, so the possibility of their first festival appearance being at Sasquatch is rather large. Pearl Jam has never played Sasquatch, and they have been touring supporting a new album, so this might be the year they play Sasquatch.
What some don't realize is that they share the same drummer, Matt Cameron, so each touring simultaneously would be impossible. Realistically, each could play Sasquatch, surrounding a Soundgarden reunion tour, and a Pearl Jam hiatus (minus Sasquatch of course).
If both acts are on the bill, they will have all six members of Temple of the Dog in Central Washington at the same time. Pearl Jam brought out Chris Cornell at a show in L.A. last October to perform Hunger Strike. That was the first Temple of the Dog performance since 2003, so the possibility of a reunion is on their minds as well. Actually, Temple of the Dog has never performed a full set with all six members, so if each band is on the lineup, expect at least a collaboration of a couple songs.
Headlining acts don't typically stick around to play multiple sets at music festivals, they usually show up two hours before their set, play, then leave a couple hours later. Sasquatch successfully pulled it off in 2007 though with a Mix Master Mike set and an instrumental Beastie Boys set one day, followed by a full Beastie Boys set the next night. Is it possible Sasquatch can pull it off again, with each band playing a set, followed by a combined effort the next night?
I'm not saying a full Temple of the Dog set will happen, but if it ever does, it will be Sasquatch 2010.