Where can I find sounds of church organs in NI?
Sonuscore have a free Pipe Organ available on their website. It even loads as a library in Kontakt.
There are also a couple from Soniccouture, suggested directly from someone from NI
They also have a free one (Pipe organ):
Also Wavesfactory has a free one (1850 Pipe organ):
Vintage Organs (directly from NI) contains various organs (as the name implies) but not exactly church ones
All of these are Kontakt libraries
My favourite one is All Saints Organ: https://www.native-instruments.com/en/products/nks-partners/soniccouture/all-saints-organ/
And a superb album made on a real organ that I would also highly recommend: https://kalimalone.bandcamp.com/album/the-sacrificial-code