Will the one-way glass be Tevarin ship exclusive, or is there a chance we can see this as a modular option for other ships as well?

We are treating the 'one way' cockpit as exclusive to Tevarin ships for the time being; for now, we are going to consider it part of the ship hull rather than an individual component (meaning the ship was designed in specific ways in order to use it.) That doesn't mean the Prowler will be the only ship that uses this tech, though... we'd love to further develop both their historical and present-day ship designs!