I'll speak on behalf of 3 month old Regis, because that's the age he was when we got him:
I don't recall him ever trying to herd anything. I think he was too busy being herded by my Collie!
He was not mouthy or nipped. He did when we first got him because he wasn't trained otherwise, and once he got the idea that nipping meant no play and a firm "no bite!" he stopped. I've never had a problem with Regis in that sense.
I really worked my butt off to socialize Regis, probably a lot more than was necessary! When I had him while living at home, I had two other dogs. I also took him to the (small dog side) dog park almost everyday, it's still his most favorite thing. When I moved out, I was right behind an outdoor mall that was dog friendly, so I'd take him allll the time. He is so different looking that he got tons of attention(cars stopped to see him!). So I never had problems with socializing either!
Things you should know.. crazy corgi moments.. Sometimes Regis would be just hanging out, laying around and the next he was running in circles around my place as fast as he could for a good while! It's so random! Now that I have Kyrie, he just rushes over to her and swiftly starts a big play fight and they run around together.
I also find that Regis is up for anything. He can lay around and veg out all day, or he can be active with me all day. Whatever I feel like doing, Regis is down for it! Kyrie.. not so much, LOL! She likes to nap most of the day away :lol-sign:
He is definitely is a lot happier being in a home with more than just one dog. This may just be him, though. But I found when I had my other corgi(looong story) he was SO much happier at home and when she had to be returned about a week later, he was so unhappy ): I just felt awful for him. Now that we have Kyrie, he's so happy. He loves to have a constant playmate, and another dog to cuddle with. Both dogs sleep in one HUGE crate and there is enough room for each of them to sleep away from eachother, but Regis always goes right up to Kyrie and lays on her. They are almost always cuddled up together if they aren't playing
Good luck!!! Corgi's are AWESOME!