Excellent! Can't wait to check out the alpha!
What platform(s) are you shooting for?
Monetizing is tricky, but if done right I think micro transactions are the way to go along with limited sponsors/advertising. Personally I would steer away banner ads as they only take away from the experience and generate very little revenue. Your idea of banner Ads only in the chatting stage (outside of the actual game) is a good idea though^^