I did some preliminary testing with the 32 bit Adelie... The 'Full rootfs' can be booted with our ordinary kernels, and logged in ('root', password 'live'). But I did not find any desktop from it (lightdm and startx did not do anything), and was not able to test it any further.
The 'Desktop', which is a 'live' .iso image, is in mac format which X5000's U-Boot does not support. I did try to bypass this by copying the contents of it to a FAT partition and tried to boot it from there, but this time bootm refused to start the included kernel ("Wrong Image Format for bootm command") and the initrd.pcc ("Wrong Ram disk Image Format"). Dead-end...
So, it seems Adélie works at least at basic level with X5000, but it is above my skills to install it properly. Probably the easiest way would be to instal it first to a PPC Mac which can use directly the 'Live' media and the included installer with graphical front end, and then simply transfer the resulting root file system to X5000. Unfortunately I do not have such machine at hands...
If there is anyone around here who has the needed equipment/skills and time to 'adjust' Amélie to X5000, please continue from this

PS. In the package listing there was mentioned Firefox 68.0.10 ESR. If it really works, it would probably be the best Linux browser available for X5000 so far. The "Wicknix" one's are already hopelessly outdated...