I would not keep any number of guineas penned up for extended periods. The couple times I had to put the flock on lockdown mine got very "punchy" after about a week.
The females can actually be more aggressive than the males. When I've integrated new birds into my mixed flock it's the guinea hens that are the most aggressive to newcomers (even if they're guineas). Guinea hens will also vicously defend a nest or nesting box they're using.
Guineas are much more prone to wander, and don't respect boundaries, roads, or your neighbor's rottweiler. If they do integrate with your chickens successfully, the more confident ones will follow their guinea friends on these adventures.
One afternoon I had the whole lot of guineas, plus a couple of my olive eggers charge off into a neighboring woodland and farm field. I figured that was it for them but they all came back several hours later. I ended up having to fence off an area for them.
Guineas are very unlike regular domesticated poultry, and they have behaviors that range from charmingly quirky to rage inducing. If your chickens are high strung breeds they will get extremely stressed out. This is doubly true if they're cooped up in an environment where they can't get away from each other.
Your guineas will want a separate sleeping area, visually separated from where the chickens sleep.
Your rooster is going to be a much better guardian against your neighbor's barking rats than guineas will. In my experience they're very good at keeping hawks at bay, but didn't help protect my chickens from the bobcat that was snatching lone hens that wandered off to forage by themselves.
