Hmm, not sure about the setup but Razor cannot be the most front else it will die too fast

Troll is not bad if you could afford to build him because he can easily kill mid row and his throw axe skill is quite good

Enchantress is not that good in Arena except maybe you have purple Windrunner

I think just try to fit in Troll if can cause a lot of people has started using Troll lately in arena already