“Halfway to Halloween” will pay homage to the classic holiday variety shows, featuring scripted skits, musical performances, and guest appearances — including David Dastmalchian (“Suicide Squad”), Kevin Smith (“Clerks”), Taran Killam (“Saturday Night Live”), Matthew Lillard (“Scream”), Jorge Garcia (“Lost”), Steve Agee (“Peacemaker”), Barbara Crampton (“Chopping Mall”), Felissa…