It is possible you could, one user @Lutiana attempted the same thing and ran into some issues, if you do solve any issues then be sure to post how you solved them.
A few small parts of my Ubuntu guide were actually created from Debian guides so it is certainly possible. You just might have to problem solve some things that you would not run into when following my guide using a fresh box and Ubuntu.
Also I know for a fact that Incredible PBX (by Wardmundy) has been setup on raspberry PI machines, but in his method I am pretty sure he installs asterisk 13 and freepbx 13, and then simply Applies the Patch Files.
In the Dslreports thread, I think a couple users have outlined how to apply the Patch file to an EXISTING install, that may end up being the simplest if you run into issues.