Those 2 roosters could live happily with the hens. As long s you collect eggs every day, and don't let any of the hens set on them for 21 days, you won't get chicks.
If they are to be seperate from the girls, they should have a safe secure structure to go in to at night. If they are not penned, you can expect tragedy at some point. And it's one heck of a horrible sound and sight when a raccoon is attacking.
But, to answer your question- We've lost 2 that jumped on to the neighbors dog pen, and 2 others to the other neighbors dog. We have 5 outdoor cats ( not mine, but neighbors cats) that have never bothered the chickens. In fact, the chickens have bothered the cats. We also had a stray kitten that came to us and lived in with our chickens( and he killed and ate mice and birds but never went after a chicken- although we did have a baby chick disappear, and it may have been him). So, it's been my experience that cats don't mess with the full grown chickens. But even though we have had no problems with the cats in 2 years- I get a little nervous when they come around the chickens. Because you just never know