I would say cycle without fish. I had one Guppy Die, and one Betta Die, and 1 Cat Fish Cory, about to die, so I quickly add Cory to me 20 cycled tank.
I would say do a Fish in cycle but it did not work for me, water changes, and adding bacteria, and add conditioner. I did water changes everyday and my fishes died. I hate to see the fish suffer. Now if you want to cycle Endler's Livebeares, that is fine, as my Endler's Livebearer withstood the cycle process as they are super Hardy. I say this from experience. Some will say not to cycle any fish, so just be careful, if you do Cycle with a fish. There I'm done ranting on the Subject at hand, just my opinion.