I gave my cats a bath with flea shampoo for dogs, think they'll be OK?

Um yeah. That was really bad. Hartz for one thing, does not do ANYTHING to help with fleas. Hartz is the worst product in the world. And using dog flea and tick shampoo is even worse for cats because it can cause them pyrethrin toxicity. You need to rebathe them with regular dawn dish detergent(no bleach) right away. If they get pyrethrin toxicity, your cats will start tremoring really bad like they are seizuring and its very toxic. If you see these signs, you have to take take them to a vet, or you could let your cats die. I always tell people that if you go cheap and use dog flea and tick stuff (esp hartz) on your cat your gonna end up spending hundreds of dollars anyway to treat your cat for toxicity. Also Emergency is solely walk-ins. That is why it is emergency. See if your ER facility takes care credit if you need to go. Try the dawn first. Maybe you can get it off fast enough before they show signs.