It was pretty challenging for me. Not so much the first three but like... Bronzong was a huge pain because of its calm mind. I was able to take it out with patience. I used my Luxray, and just kept doing Charge and Swagger.
The Garchomp was a huge pain as well... I forgot how I took it out, but... It was difficult for me, since my team had a huge ground weakness...
I had, Luxray (weak to Earthquake), Steelix (Weak to Earthquake), Weavile (Weak to Brick Break), Lucario (weak to Earthquake), Empoleon (Weak to Earthquake) and a Staraptor. ._. It was a ten minute battle for me, in which a lot of strategy and luck was involved... and my team was also severly underleveled as well... By the end of the battle, my highest level pokemon was my level 56 Luxray. Steelix and Weavile were barely in mid-40's. But, I tend to roll that way.