It sounds like you may have another flock penned separately? If you do, how big is their area, how many chickens are in it, what age are they, and what sexes are they? Is that Polish female laying eggs yet? How much room do the two mature rosters, the polish female, and 7 pullets have? If you do have a different flock, why are those mature Polish roosters penned separately? Just trying to figure out what you are working with.
To me, whether or not that Polish female is laying eggs is a huge question. Their behaviors can change dramatically once they start to lay.
I personally do not believe that the ratio of males to females is that important. I've seen too many examples where ratios that freak some people out work great. I've seen where perfect ratios are horrible. Removing one of the boys might help, or it might not.
Adding more hens to the mix might help, or it might hurt. She would have to integrate with the girls. That might go very well or it might be pretty violent. You can always try it and observe. If you need to, be ready to separate them.
You want to hatch her eggs with her mated to a Polish male. It takes an egg an average of 25 hours to go through a hen's internal egg making factory. It can only be fertilized during the first few minutes of that journey. That means an egg cannot be fertile the day that a mating takes place. Say she was mated on a Saturday, Saturday's egg cannot be fertile from that mating. Sunday's egg might or might not be, depending on timing. Monday's egg will almost certainly be fertile from that mating.
A rooster does not necessarily mate with every hen in his flock every day. He doesn't have to. The sperm is stored in a special container inside the hen near where the egg starts its internal journey. That sperm can remain viable for between 9 days until more than 3 weeks, you don't know how long. This provides a possible solution and a potential problem. If that Polish female came from a flock with a rooster she may be carrying his sperm for another three or more weeks. You'll need to wait that long before you save any eggs to hatch to be sure it is one of your roosters. But if she came from a flock with no roosters you can separate her for a week after a mating and collect her eggs before needing to put her back for another mating. Just watch the timing.
I think you have a lot of options but I don't know which one will work best for you. Good luck!