Hi. I did not respond to your other thread, but now that I see the cage, I can. I believe that your cage is too small to expect Peanut to share with another bird. While it is really up to the birds involved (if they will get along nicely or not), I think it is asking too much to put them in there together. Regardless, you would not want to just bring a new bird in to share another bird's cage, unless the cage were a very large one, many times the size of the cage Peanut uses now.
For a little perspective, think how you would feel if you were asked to live in just your bedroom and share it with a stranger who liked all your favourite things as much as you do and wanted to use them all the time.
I love to see photos of how people have arranged their cages and play areas. Yours are very creative. I especially like the one in the plant pot at the office.
I would like to suggest you give Peanut some additional toys that are meant to be destroyed. One of our forum members gives her bird toys made of popsicle sticks, which he loves. I give my bird small wood blocks, toys made of dried grasses, and (the simplest toy in the world) a clean jute cord with bits of cardboard strung on it.
Peanut certainly is a pretty bird.