Hey antimoine, feel sorry for your accident.
I'm throwing a house party Christmas time... with college students... so I'll be careful of the yeast bottle as well.
I've never had this happen to me, so I don't know what can help personally.
I know flocculents only make the suspended floating yeast clump together and gather on the bottom of the tank, so you'll have to mechanically remove it yourself. Floss might not be super effective as the yeast will grow anywhere, kind of like trying to remove algae with floss. Maybe take your fish out to prevent anymore casualties until the water is cleared up? This might also let you clean the tank more aggressively w/o stressing the rummynose. As long as there's any source of food for the yeast in the tank, it will probably keep growing. I keep rummynoses too and they're like super-sensitive to stress, so it might be a good idea. Oh wait... you can't see them. Maybe a massive water change, then while you can see some, take them out? As for the plants, don't know either. Maybe take them out as well. For the yeast growing on the plants, maybe dip it in a solution of some kind that will kill it, don't know what kind of solution though.