Most probably not. Usually, such titles suggest a fictional or imaginative storyline rather than being based on actual happenings. It could be a work of pure imagination or inspired by various fictional elements.
No, Totally Killer is most likely not based on a true story. Usually, such works are explicitly stated as being inspired by real events if that's the case, but there's no indication of that here.
One interesting storyline is when they have to go undercover at a fashion show where the villain is using the models as part of an evil plan. The spies have to blend in as models while also trying to figure out what's going on.
A lesser - known but interesting Totally Spies vampire fanfiction is 'When Spies Meet Vampires'. It focuses on the individual relationships between the spies and certain vampire characters. It's a more character - driven story that still has the elements of the spy world and the vampire lore.
A totally awkward love story might involve one person being too shy to make a move, while the other is clueless. They keep missing opportunities and end up in comical and cringe-worthy situations.