I’ve heard that both Faverolles and Australorps make great, docile roosters, but I also know every roo is different and I don’t want to generalize and just “hope for the best”.
To me, each chicken has its own personality, regardless of breed. If you read enough stories on this forum you will find a rooster of any breed that was great and another of the same breed that was a terror. I put no faith in breed when it comes to behaviors.
Is giving one a chance too risky with my kids? Possibly both if it works out with additional hens?
The million dollar question. You'll find people on here that are a definite "not no how, not no way". Others will say to give them a chance.
I grew up on a farm with five kids and free ranging chickens, including roosters. We didn't have any problems but the chickens were a distance from the house where we played. The kids did have the chores of gathering eggs and feeding the chickens some corn in the winter but there was really little direct contact. There were not many chances for something to go wrong. So one factor for me is how much room do they have and how much contact will there be. The more separation the better. I'd be nervous is they were on top of each other.
I'll go through this spiel. Why do you want a rooster? The only reason you need a rooster is if you want fertile eggs. Everything else is personal preference. Nothing wrong with personal preferences, I have a few of them myself.
People mention security. Some people free range flocks of hens for years with no predator problems. Some people with a mature rooster are wiped out very soon after starting free ranging. You can get some security benefits with a rooster, from what I've seen they are more alert to possible dangers but often the dominant hen will assume those responsibilities.
My general suggestion as to how many roosters to keep is as few as possible and still meet your goals. You are not guaranteed problems with more roosters, but the more roosters you have the more likely you are to have issues. I don't know what the best answer is for you, 0, 1, or 2.
If not, should I get rid of them now or wait to cull them later on so they can go in the freezer?
Purely your choice. Cockerels are seldom a danger to kids, each other, or the pullets until they reach puberty. That can start before 12 weeks or wait until after 20 weeks, though I think around 16 weeks is more normal. Remember, each has its own individual personality.
If you think you will get so attached to them that it is hard to get rid of them I'd suggest as young as possible. If you can handle butchering I'd wait until they are about 16 weeks old or their behavior tells you it is time. You can eat any chicken of any age but 16 weeks is when they tend to put some meat on those bones. Don't expect a lot of meat since they are not Cornish Crosses but you should be able to easily get a meal out of one at 16 weeks.