I looked up proper acclimation techniques on YouTube and have now acclimated the guppies into the 5gal with the gourami. They seem to be doing just fine. They have piqued the gourami's interest and he has been checking them out. He hasn't tried to eat them yet so that is good!
Also- king Neptune the betta fish is hanging in there. I can't tell if he is less bloated, but when I get close to his bowl he swims away with much vigor. Still keeping an eye on him and I'm going to check the fish store for a larger small tank that would be more suitable. Hopefully I can find something decent.