For a small dog, I suggest a rat terrier. They are fairly high energy in general (though ours never were) but ours never messed with our other pets...although there are probably people who have had different experiences. Also, I was raised with them, so ours were always good with kids, and as your youngest is 7, i think, I don't think you really need to worry about that, because at 7 kids know how to behave around dogs (or can be taught easily).
More medium sized dog, I love corgis. They seem to get along with everyone, although not as great with other animals...don't seem to be quite as high energy either.
For a large dog, a golden retriever is a classic family dog. They love to please their master, and while they can be a handful as puppies, they learn quickly and settle into awesome family dogs.
My min pin experience is limited to only one, but from her, I sense that they are slightly insecure and like to be around someone all the time. She is also a proved chicken killer, so I don't think they would be very good around chickens. She is sweet though, and this one is fine with new people and loves to cuddle.