Unfortunately I can’t help much at all.
I’ve never run ambilight/boblight etc (nor cared to bother trying).
As newkind mentions, there were 2 different tutorials for this on Crystalbuntu.
One is still in the kodi forum:
http://forum.kodi.tv/showthread.php?tid=101406
and the other can be found in the internet archive:
https://web.archive.org/web/20120118120127/http://stmlabs.com/forum/topic/tutorial-appletv-ambilight-based-on-ws2801-and-arduino
Maybe the author is still active and can be contacted via the kodi forums ?