Dear FreeBSD,

solved via a tip from Paul, with the addition of the following lines
to /boot/loader.conf:

console=comconsole
hint.atkbdc.0.disabled=1
hint.atkbd.0.disabled=1
hint.fdc.0.disabled=1
hint.psm.0.disabled=1

In addition, the guide I was using mentions defining md filesystems in
fstab, thus:

md /var mfs rw,-s8m 2 0
md /tmp mfs rw,-s8m 2 0

...instead of in rc.conf, as:
varsize=8192
varmfs="YES"
tmpmfs="YES"
tmpsize=8192

This method (fstab) proved not to work:
...
mount: /var/tmp: No such file or directory
Mounting /etc/fstab filesystems failed,  startup aborted
Boot interrupted
...

I'm not sure why, but I'm happy it's now working.

Thank you all for you input.

Best wishes,
boink