Welcome Matt (no pun intended)
Although I applaud you getting rid of the goldfish bowl, 60L tanks are really not big enough for goldfish, especially comets. I personally don't like to see comets in anything smaller than a pond. The fancier varieties, like the telescopic eye, are different as they do not swim about like the short finned varieties.
I don't know how many fish you already have but you will need bigger if you are going to add the fish you say are coming next week. You are also going to have a problem with cycling if they are all added at once (depending on numbers).
What is a butterfly sucker? If you mean a hillstream loach, these fish are tropical and need water with a high oxygen content and good water flow. Waterflow is something fancy goldfish do not like.