For the time being it would be fine since all the fish are small, in my quick research about Sun Catfish they will outgrow a 55g tank though. Planet Catfish lists adult size at over 17", far to big for a 55g tank. The JD will also want a larger tank once it's grown, the shallow depth of a 55g just isn't enough in my opinion.
I think eventually you will need to get a bigger tank. For now it won't be bad while they are small. So it all depends if you will be able to upgrade or not.