Them building the exchange before running any IEO (if they do plan on running one) is surely a good decision. I'm pretty sure that was their plan from the very beginning but let's not forget that in order for their exchange to work, they need a strong community and followers backing them up.
Not answering inquiries about their project not only raises more questions and speculations but also decreases their initial follower's confidence and trust towards them. This in turn also sends bad signals towards those potential users and traders. If the team wants to maintain and continue to grow their community, they need to be present to answer questions or even make discussions with everyone.