That's cool that you have different kinds of mutations. They are all so pretty and colorful! My conure isn't loud, either, but he does scream sometimes when he wants out of his cage (which I ignore because it's really loud and I don't want to reinforce it). He gets let out when he's quiet.
He's a very good bird but he is demanding and really active and I don't think I could keep up with 4 of him!

For one thing I don't have enough shoulders or hands because he always wants to cuddle or get head scratches.
I often wish he had a GCC friend and if I knew for a fact that he would get along with another GCC I would get one in a heartbeat! However, he is a bully and bullies my Poi (who is twice his size) so I have my doubts that he would get along with another conure. Since I can't be 100% sure he'd be friends with another GCC I've ruled out adopting a second one.
GCCs are great birds, though; they are super hilarious.

A "conure tornado"---I can only imagine!