Oooo! Ayam Cemanis and EE are 2 of my favorites! Ok so yes, overmating is definitely the biggest concern. Saddles can help, however, overmating can also cause feather-loss on the head and neck, which the saddle will not cover. The trouble is that 2 buddy roosters may like each other, but they still enjoy competing with each other. For example, I used to have multiple roosters with a flock of around 20. One rooster would go mate with a hen, and his buddy would follow him and watch, sometimes impatiently pecking the hens head while the other rooster was still mating. Then as soon as he gets off, the next boy would jump on. The hens did not like it. Overmating is not just bad because feathers get pulled, but because of stress. Normally a single rooster will mate with each of his hens once per day, which is normal and healthy. But I've noticed when there are multiple roosters, both of them will mate with each hen MULTIPLE times a day. (poor hen, she's definitely not having fun anymore.)
Your chickens are free range, so you may not have as big of an issue with this, but I wouldn't count on it either. If you want to see how things go, you can and make adjustments as needed. However, I normally don't recommend multiple roosters unless each rooster can have about 15 hens each, AND they free range.
Another little known alternative that a lot of people overlook, is a bachelor coop. A coop with all boys can be a very peaceful and pleasant thing. As long as they are not too close to a pen of hens, they usually won't fight because there is nothing to fight over!
As far as your child chasing hens, I'm not going to be arbitrary because if depends on your rooster. I personally chase my own hens around in front of my rooster and I have no problems, but that's because my rooster is a coward and wouldn't dare raise an objection with me. He also knows I'm not going to hurt them. If your rooster starts to exhibit protective behaviors towards his ladies when your child chases them, you may want to be ware, that means he views your child as a threat to their safety and he may retaliate. It just kinda depends on his demeanor.