Ibuki Mioda will be immune (because spoilers) and likely be doing little of importance besides hiding out at house 7 and taking care of the Tanaka kingdom. Well, there's also a brief thing discussed with Alastor-mun that she'll help with.

That said, because I have no big plans for this event, I'm open to ideas if anybody wants to do something with Ibuki.

Since she's been having something of a rather difficult stay at Ruby City so far(despite keeping a strong front most of the time), I'd rather that she not get targeted for anything that'll add to her despair misery. Especially since a lot of her friends are going to end up diseased and/or hurt during this event.