With guppies, if you have at least one male and at least one female, you will have babies, guaranteed. You should have more females than males (2:1 or 3:1, or the males will just keep chasing the females.
On another note:
-The neon needs more of it's kind, at least three, but more would be better.
-What kind of catfish? If it is a cory, it needs more as well, if it is another other kind, it may very well grow too large for the tank very quickly.
-The pleco will be too large for the tank, even a dwarf.
-Please don't tell me that the goldfish are actually in a bowl, they need a tank with filter. One goldfish on it's own needs about a twenty gallon tank....