Estrogen issues should not be a problem until your cycle is over into PCT. At that time you can get the estrogen rebound and the AI will be needed then.
I got gyno from beast, so it is possible, although uncommon. (1% of people suffer from receptor crossover, that may allow you to develop gyno from beast)
You need an AI on hand, but i wouldn't use it unless absolutely necessary. And aromasin should be fine if needs must.