Welcome to the forum, glad you joined
I'm not too worried about the mixture of breeds, especially since they are being raised together. Sometimes Polish can be picked on because of their weird feathering but usually that's when new chickens are involved. Any chicken of any breed can become picked on, even by chickens of the same breed. It doesn't have to be a physical difference, it can be personality, but chickens raised together usually get along.
I'm not worried about your male/female ratios. I've had a 1 to 5 ratio (3 and 15) and had no problems. Often I overwinter one rooster and six hens. I've had problems with larger ratios. Breeders often keep one rooster with one or two hens the entire breeding season without issues. If you read enough posts on here you will find examples of these problems with one rooster and over 20 hens. Your ratios don't bother me.
How much room do you have? The more room you have the more having multiple roosters is likely to work. I've had two roosters hang out together all day, but that is kind of rare once they reach maturity. What typically happens is that each rooster sets up his own territory separated enough that they are not in line of sight. Each has his own harem. Not many of us have that kind of room. It is possible they can work out an accommodation with less room but the more room you have the better your chances. You can improve the quality of the room you have by having multiple feed and water stations and having things in there to break up the line of sight.
There is a big difference in cockerels and pullets versus roosters and hens. If you can get through puberty things normally settle down but puberty can be rough. The cockerels' hormones are raging and the pullets are too immature to do their part. The hormones are telling the cockerels to mate every female in sight. That's not to fertilize eggs, the pullets are probably not laying eggs. Mating is how the cockerels establish dominance. The one on bottom is accepting the dominance of the one on top, either willingly or by force. At that age it's usually by force and can get pretty violent. When they finally mature it's usually willingly and much calmer.
When you have more than one male, they will establish which is boss. Sometimes they fight to the death, often they reach an accommodation. Again, room is important. One way chickens survive conflict is that the looser runs away. This can be pecking order fights between hens or flock dominance fights between roosters. Often the loosing one quickly decides it is better to run away than to stay and fight. So it runs. The winner may chase a bit but usually gives up fairly quickly. Often the pecking order or dominance fights are more about chasing and running that actual fighting. But if the loser cannot get away, the winner doesn't know he won and keeps attacking. Chickens die because of that lack or room.
Having plenty of room does not mean that there will never be a fight to the death. Sometimes the loser just refuses to run. Sometimes the winner just won't quit chasing until he kills his rival. Individual personalities come into play.
Why do you want roosters? What are your goals around those roosters? The only reason you need a rooster is if you want fertile eggs, everything else is just personal preference. Personal preference can be pretty strong. I suggest you keep as few roosters as you can and still meet your goals. Not because you are guaranteed problems with more roosters, but that problems are more likely. I'd suggest having a separate pen ready where you can quickly put one in a hurry if it becomes necessary.
