What a lucky spoiled betta.
I once put a pet store betta into a 55 gallon tank. The poor guy was so out of shape from living in a jar that he couldn't swim for the first week. He'd just kind of float around on the currents. Even after he built up some muscle, he never did get the concept of living in a large tank. He'd swim for maybe a foot, turn around, and swim back in the other direction. He seemed lost without a glass wall to define his territory.
In a mixed fish tank I prefer Amano shrimp or red cherry shrimp over ghost shrimp. Ghost shrimp can be a little aggressive. My favs are the Amanos, as they are bigger and can't reproduce in fresh water. Red cherry shrimp reproduce like snails. I always feel bad when I accidentally vacuum up a shrimplet while cleaning the tank.
I really want a tank of mixed dojo loaches and goldfish. Dojos prefer cooler temperatures (65-75), as do goldfish, and they get get pretty big, again as do goldfish. Alas, I don't currently have a place where I could set up a 200 gallon tank to show them all off in their full splendor.