A lot depends on the age of the father rooster. If he is over 3 years, then I would be tempted to keep one...for a while anyway. A spare rooster raised up in a multi-generational flock is a nice thing to have. This is because I would expect a rooster at that age, to be either near the end of his life, or I liked the young rooster better. Eventually, I would be planning to go back to a single rooster.
But MORE depends on your numbers and space. Roosters need more room than hens, and multiple roosters need more space than one, by quite a lot. And even then, it quite often does not work to have multiple roosters. Roosters are a crap shoot, as in sometimes they work, and sometimes they don't. Their behavior on Monday, has very little influence on their behavior on Tuesday.
I would not want to keep full time multiple roosters with less than 25 hens. My own personal preference.
There’s no way to tell if there will be peace or chaos... you can try having multiple roosters, but in my personal experience, unless you have two coops / runs / flocks of hens and complete separation, it will be a nightmare and you’ll regret it. We had a similar situation, and the resulting cockerel was way bigger than his bantam dad, since dad mated with a standard BSL. He almost killed his dad, and we had separate areas for them which became a huge PITA, esp when you’re pressed for time in the morning and now you have to take care of two flocks / enclosures.
What are your goals for the boys? Why do you want to keep one? The only reason you need a rooster is if you want fertile eggs. Anything else is personal preference. Nothing wrong with personal preference, I have a few myself. But I recognize that as a choice. My suggestion is to keep as few boys as you can and still meet your goals. That's not because you are guaranteed problems with more boys but problems are more likely.
You can try keeping more than one male with your flock. Sometimes that works out, especially if you have a lot of room. Sometimes it is a disaster even with a lot of room. You can build separate living quarters and keep them separated from each other or from your flock. You have lots of different options on how to go about it. But if it turns south it can go south really quickly. So I suggest having a Plan B, which for me is to have a place ready to immediately put one if you have to. It can get that serious that quickly.