Annalisa's characters James Potter was at the viewing party for Rocky Horror, hanging out after the viewing to talk about Frank-n-Furter. He'll probably just be kind of ??? at first but then will apparate around trying to check on his fam and friends.
Ronan Lynch is somewhere with the Gangsey and probably Baelfire & some THG types, for Bae's birthday. He'll just start saying "what the fuck?" a lot.
Katniss Everdeen and Annie Cresta are potentially also with Bae's group. Annie will shriek when the lights go down. Katniss will keep her cool and try to get everyone to stay together and move to somewhere else where they can figure out what's happening.
Matt Holt was building a robot for robot chases. He'll make sure bb!Tony's head is okay and then go off with Tony & Pidge & Hunk & whoever else to check out the ships/robots.
Mal Oretsev is probably somewhere with Alina, who will likely do her light magic to light up wherever they are and try to go and help.
Frank Castle is ??? idk where, probably with his people, otherwise he'd go find his people immediately.
Same for Sam Winchester, with the trying to check on his people immediately thing. He'll also make sure anyone else around him is ok though.
Rhy Maresh was probably having dinner with Alucard and/or Kell and will get up to figure out what's going on.