>Would this guide compile a non-PAE requiring kernel?
Only if you select the correct configuration options, I don't know what all
you need exactly.
>Which kernel should I download to put in the install CD?
For best compatibility, select the same version as the original. Others might
work as well.
>What file should I extract out of the completed .deb and put in the Trisquel
iso?
Well, you need a kernel and an initrd. You could try using vmlinuz from
/boot/ in the .deb with the initrd from the .iso or you could install the
.deb on your system and then take the matching kernel and initrd from your
system's /boot
