I'll post more on this later, but here's one thing for now re the S.H.O.W.E.R. thing. Being around vampires brings out the werewolf in Angua far more strongly than usual. Being around a full moon brings out the werewolf in Angua much more strongly than usual. Despite her best efforts, being around a vampire at full moon made a lot of werewolfy things about Angua far more prominent and less controllable than they would normally be. So no wonder she had an unusually bad reaction to the notion of a shower. But, she still got in - which is why she's still the Angua we know.