Air pump advice needed?

Yes maybe the smaller pump would have been ok but the bigger one will run an aerator and a filter, which the smaller one might not have done. You can certainly use the bigger pump for two bubble ornaments - you need a "T" or "Y" connector which almost all aquarium shops should stock. Don't worry too much about the pump, it will probably last longer than the small one and will cope if you decide to get a second or bigger tank.