Doctor update: it's not scarlet fever, or strep at all. Our doctor's best guess is the
roseola virus, aka "rose rash", because it showed up after a three-day fever. Normally, it wouldn't be treated, but both kids are getting antibiotics starting today because in addition to that virus, they also both apparently have raging ear infections in the same (left) ear. Which is funny, since ear infections aren't contagious.
So I guess that means two separate diseases? No wonder they've been such miserable little monsters the past week -- they must have been feeling awful.
Of course, this doesn't really explain what Kevin or I have -- roseola usually only happens in young children -- even Kavi's a little old for it. So perhaps we have completely different viruses altogether. Joy.