I've got to backup some data before experimenting, probably this weekend. Research suggests that it might be possible but I am still fuzzy on many of the details. For the record, and those who wish to follow, here are a few relevant data points:
https://wiki.freebsd.org/UEFI
https://lists.freebsd.org/pipermail/...st/048141.html
https://svnweb.freebsd.org/base?view...evision=294999
https://www.freebsd.org/news/status/...FI-Boot/Loader