IDW has over the last week started leaking out tidbits about the new Arc called "Mass Hysteria!". Among the details known is that it is a eight parter that starts up after (Volume 2) Issue #13. It will begin in February of 2014.
Among the first things one can notice from the second tease that includes a gang of Ghostbusters battle a octopus type monster is that both the original team and the
"new" team are in it. However, it also includes the three nice ladies from the
Ghost Smashers and the
Rookie.
Other notes... Erik Burnham is teasing that
'there may be a return of an accountant' meaning perhaps Louis Tully is not restricted from the comic series anymore. He also notes that the shorts on the ladies is not planned for the story arc and maybe the artist was going by the cover art to (Vol 2) #1. (Thanks Mrmichaelt for passing this along!)