The nearest that WOJ has gone is that instead of tapping into the power of a temple he taps into the threshold. Maybe he observed how Harry built his wards on his pitiful threshold as a ‘cheat’ and uses a similar cheat to power up. Because it worked so well with Harry’s threshold it worked even better with the Carpenters.
If the Castle basement becomes Harry’s home and the rest of the Castle a wider institution of learning and contemplation (and yes Harry claims to be meditating in the new short story), Mouse will have a choice of power sources, a main and a back up generator. Deconsecrate the temple there is still the threshold, mess up the threshold then there is the temple. That makes things difficult for My Shadow.
