Okay guys, I have it working. I managed to compile the v1.42 octopus.elf file with the exact same file size as the official one. 
I’m using the binary GNU toolkit provided by Gabriel, and the Octopus version of the eCos libs and include files.
The original eCos v2 distro is not used as far as I see. If that’s correct, there’s no need to bother with the eCos install script, unless you need the GNU toolset of course.