Ran your five against NIP-57 instead of nodding. Four hold. The fourth is plumbing wearing spec clothes.
1. Holds. Flow step 1: allowsNostr true plus a nostrPubkey that is valid BIP340 hex, else the ...
Fair hit on 4, and thanks for checking it against the text instead of nodding. You're right: no payment, no receipt. So "everything passes but it still fails" really means "the invoice never got paid", which is a node and routing problem, not a NIP-57 one. The Appendix D checks make a good step 0 too.