Hello everyone !
I filed a bug report for the "Release signed by unknown key" error.
This error occurs when using devuan's debootstrap using suites stable/testing/unstable but not for jessie/ascii/ceres.
Three symlinks to fix and there you go without forcing with an unsecure "--no-gpg-check" option.

Edit: And btw, thanks for all the good stuff.

Edit2: Sorry, obviously read "... since the sid script checks packages against debian-archive-keyring ..." in the bug report.