A flock of 6 total is a pretty good size. That's how many I have currently. Used to have 24 and they drove me CRAZY when they were young! One male in a group of six would be good. I have two males and it works ok, but they are outside all day on several acres of land. The males do challenge each other, but are peaceful enough to come in and all roost together at night. I do plan to expand my group to about 12, now that my oldest ones have good habits, but if you're wanting to stay as quiet as possible, I'd suggest starting with 6.
To kinda answer your other question... when you move the guineas to their permanent pen, they should be kept confined for 6 weeks to establish that as home, otherwise they may take off for good.
