You're integrating. Chances are it's going to be a problem. Better to be proactive with changes now.I’ve had 6 birds with no problems. I had to give away three because they were roosters
Free range time helps but only if it's for a significant amount of time each day. You might be able to get away with a smaller coop, but not a small run + occasional free range. What Mrs K suggested was a bare minimum for run space, I would go bigger if you have room to do so, like 100 sq ft, to allow space for clutter which will go a long way in reducing aggression: https://www.backyardchickens.com/threads/a-cluttered-run.1323792/I can add on to the run but we let them out to roam the yard a couple times a week.