How terrible to have to come home to that!
That would be my worst nightmare when it comes to the orchids. Hope the Phyton works for you.
If you have some that aren't too badly affected and the rot isn't in/near the crown, I recommend cutting off /excising the lesions, separate those plants and hope that's enough. 2 summers ago I caught an Erwinia infection very early on my orchids, and cutting off affected leaves and treating once was enough to stop it in it's tracks. Some Phals look really beat up now with large chunks of leaf missing, but at least they're alive!