Dan said on his blog that there will be alot of guest stars from previous iCarlys:
"Griffin" - Carly's bad boy ex who's obsessed with Pee Wee babies
"Dr.Dresdin" - The doctor from iFight Shelby Marx who gave Spencer the allergy pills with odd side effects.
"Marty Klemish" - the Bushwell neighbor from "iEnrage Gibby" who hugs Carly, consoling her about Spencer's death (of course, Spencer was only reported to be dead). "Chuck" - The evil 6th grader who always torments Spencer
"Lewbert" - Nasty doorman
"Ms.Benson" - Freddie's mother.
"Sabrina" - New girl that Freddie has alittle crush on (according to Dan)