As long as I don't distribute the resulting binary there should be no legal implications.
The problem is that neither your install or recover CD won't have it enabled by default, so if you have a problem, your hard-drive won't mount.
https://github.com/Tomas-M/linux-live
While the current generation of "make me a magic shiny debian image" is:
https://github.com/larswirzenius/vmdb2/
(I went looking for some tool I've used in the past, which may, or may not, have been "live-build").
In general though, just pulling down a dkms zfs module into any working recovery image via apt should work.
But not if you don't have net access [ed: or a lan apt mirror..].
edit: including my referral link here will probably result in negative karma, but i'm desperate for points!
[1]: https://m.do.co/c/8c882a721944
The problem is that neither your install or recover CD won't have it enabled by default, so if you have a problem, your hard-drive won't mount.