I personally would lean toward the butter fire. I love fireflies, but i would bet you have more pastel combo females than butter combo females (and if you dont the pastel combo females would be cheaper to aquire)

either way you go I would look for some vanilla combo females to go with that male. But you need to stop and evaluate what females you have and what combos you want to make in the future and go with the animal that works better for your future plans