@Gertjan
The "old" pfSense-CE-memstick-2.7.2-RELEASE-amd64.img.gz worked! I'm now up and running on my new hardware with a 10Gbps WAN connection... swoosh!
Thanks for the quick and great support!
Lesson learned: Always perform a clean barebone install using the legacy USB installer, then restore the backup, reconfigure the WAN/LAN NICs, reinstall packages, and restart.