[PvK]

I'll double-check the religious facilities (and I think I already tweaked them a little recently), but in general yes they may be much cheaper in terms of resources than equivalent mundane facilities. The main requirement for an effective temple, it seems to me, is devotion, rather than high-tech materials. This is represented and balanced via empire start points (paying for the Devoutly Religious trait), rather than by resource costs. Note that the main power of the Religious trait in the unmodded game, the talisman, is much reduced in effect, cheapness, and ease of access, compared to the unmodded game. So I think having temples cheaper in resource cost than mundane facilities is ok in general.

PvK