If you are ABSOLUTELY CERTAIN that they have not ingested any foreign product, then,It appears that they got a bad batch of food. The pink vomit is probably food coloring that is in the tuna and egg food. Look at the cans and do not give them any food with that lot number. Try to feed them very lightly. Dogs are different. Their digestive systems can tolerate a multitude more than a cat. Anything a cats sensitive digestive system detects is bad will come right up. Call the cat food company tomorrow and report this and they will send you a whole case.
If the vomiting contiues into tomorrow after you are no longer using this food then call your vet.
Dedicated to Cats and the people who love them!
Please press ACCEPT if my answer was helpful and leave feedback Thank you! Terri