Interview went well and they did a combo interview. Sadly it seems when my GC was first done 3+ years ago they incorrectly put me down as a CR6 category (GC for someone who entered as married to a citizen) instead of CR1 (someone who entered as a K1 visa holder). Apparently a common error so they are having to go back and make some clerical adjustments before approving this (and still waiting on my background check).
All in all a good experience, took a while due to the error in the GC. Hopefully should hear back in the next month or so. The process continues! Good luck everyone.