Hello, We have the same goal.
Right now I only have ways to tell you how it doesn’t work. I hope in the next few days I can tell you something more.
I think that with the Onion package, you can only read the PN532 from the UART.
Our goal now is to compile version 1.8 of the libnfc (https://github.com/nfc-tools/libnfc/releases/tag/libnfc-1.8.0) to use the PN532 from I2C and then replace pn532 with pn7150, which is more current and cheaper.
If you get anything publish it please, I’ll keep you informed.