BRNSURGE will be direct replacement for BRSURGE? BRPSURGE an option for PON Loadcenters?

Yes, BRNSURGE would be the direct replacement for BRSURGE. Both would have the pigtail wire to connect to the neutral bar. It would be compatible with both legacy loadcenters and plug-on neutral loadcenters (which still have set screws for wire termination on the neutral bars). If you know that the loadcenter is a plug-on neutral type loadcenter then BRPSURGE can be used for the PON feature instead of the pigtail.

Refer below link for more details :https://www.eaton.com/content/dam/eaton/products/residential/electrical-safety/NEC-surge-protection-CC003013EN.pdf