Our young ones love to get misted with a water bottle to the point where they are totally soaked and cannot get enough of that. They never tire of this game no matter how long I have sprayed them they want more of that They can learn to speak in somewhat squeaky voices, but their ability in this is somewhat limited. However they do make up for this with their cuddly personality. They can sit for hours on your shoulder and just nestled on your neck or want to be held. As for breeding they are quiet prolific and start breeding between 2 and 3 years.
Various sizes help prevent foot problems.
We use grape vines which they love, since they can chew on them also. And Sun Conures love toys, the more the better. We make most of our toys ourselves, since bought bird toys can get quite expensive, but there are also some very good ones on the market. Stay away from toys with ropes, they will unwind individual strings and we found one of our suns hanging upside down by his leg, he was not harmed but could have easily been. I have heard of other people having the same problem.