Thank you all for your replies. I guess I should add he's never been bred, and he is the only horse here right now so I don't really know how he acts towards others. We got him from a mini farm, I did notice he stood near the fence looking at the girls (about 600 feet away from him), but he didn't pace the fence or act nutty. He has been much like a dog, we have trained him so far that I can put the 2&1/2 year old on his back and lead him around with no problems. He lunges well, stands for grooming, enjoys baths etc. My daughter has brought him in the house 4 or 5 times, he just walks around checking things out and then migrates to wherever the people are lol His only issue is when you feed him, he is protective of his feed (not hay though). He just pins his ears and lets you know dinner time is not a good time to visit with him

He will kick at the dog while eating, but as of yet, not the people.
My daughter is eager for a pony, but I don't want to rush him or bring out any bad behavior because he has been so very good. On another note, because he is a stallion (approx. 6yo) he has lived most of his life pastured alone, could that cause problems as well bringing in a pasture friend?
Thank you all again for your input, I really appreciate it