Ahhh... I believe I've discovered a mistranslation in Strange and Bright Nature Deity. In the chapters where Reimu summoned bullfinches to peck on lies, it's not from the celestials (which wouldn't make sense anyway since celestials like Tenshi are Buddhist.)
No, "Tenjin-sama" here is actually Sugawara no Michizane. And yes, according to Wild and Horned Hermit (Chapter 15), the Hakurei Shrine used to worship Michizane at some point.
