Hi there! Welcome to the forum! We are delighted to have you and Petey with us! What a beauty he is. I love his colouring! I honestly don’t know much about true blues and dilutes but others on the forum are quite knowledgeable so hopefully they will chime in.
I love the doggie in the cage for size comparison. When I first saw the photo, I was so confused - LOL! But that is a really nice sized cage for a Parrotlet. It could be good for 2, but the thing about parrotlets is that they are very territorial and there is no guarantee that they will love well together. Quite the contrary, actually. They can be quite vicious and can seriously injure or even kill their companion. Vigilance is key in introducing parrotlets particularity in a cage setting. You would have to be prepared to house them separately if one or the other shows any aggression. Even a divider may not work as they can Vite toes and cause injury. The decision on whether or not to bring another bird in also has breeding implications - you would need to be prepared for the possibility that they would mate if his companion was a female. This is not to say that getting another bird is a bad idea - it isn’t - just be sure you know what the risks are and are prepared to manage them. We are always here to help in whatever way we can!
Looking forward to hearing more about Petey!