I have seen my RI Red Roo mate with lady Guineas several times, but who knows if there have been any progeny. Most of the Guinea eggs have been eaten.
Re mean. I guess I should not generalize. I am sure there are nice Guineas out there, but not living here! I did raise them in a box, right along with my chickens, and from there into the coop.
They have been awful. They chase my poor hens every chance they get. When they lived in the coop they would not let the chickens eat. Even if they were not hungry, they would chase the chickens away from the food, just because.
I finally had to move them out of the chicken coop, which was difficult, and my egg laying went WAY up because the chickens had enough to eat and because they were not being picked on.
Then the minute I let the chickens out of the coop in the morning, the Guineas would instantly start to chase them. If I have a treat to toss to everybody, I have to stand there and make sure the chickens get their share, and the chickens have learned to eat and peck around under my feet.
They do seem recently to have worked things out better, but these Guineas really are mean, regardless of how they were raised.
My gentle Peafowl, and they have a reputation for being mean, have never acted like that, and I have had them for years.
The Guineas are great for eating bugs, though. They are also good watchdogs, but so are the Peafowl. And of course the dogs are good watchdogs.
I truly did not mean to insult your Guineas. I am sure there are nice Guineas out there, and of course you like your own babies!