Nice. Is there any response back beyond the ln invoice being paid? Just like the ["OK, ...] R?response from relays? Also, do you have a working draft online for this nip?

No response needed. Relay keeps track of the invoice and grants access as soon as it's paid. People can fake payments on Nostr, but they cannot do it on lightning. Not draft yet. I need to do some final tests with the invoice db @Mazin has, but it seems to be working.