All I can do is monitor today and see if Bette is sick or if it's the treats or the dry food that is making them ill. There could be a virus the girls are catching from each other since they are siblings and cuddle and groom together. Their brother doesn't eat treats or dry food and so isn't vomiting but he does cuddle and groom with them. Baby and Cooper eat the same dry food and treats and are not vomiting.
Later, when my husband gets home, we will take their temperatures. I won't take them to the vet yet unless they continue to be sick today or if their temps are high. They don't seem warm; they don't seem dehydrated; and they are not lethargic although Bette isn't her normal running around self. She seems tired but not worn out. I'll give them water by mouth and monitor their breathing. When a cat is sick-even a cat without HCM-if they are ill, sometimes the breathing will increase due to discomfort.