What collaboration? There is no collaborating here. lulz.
Obviously I don't know for sure but I'm sticking to my theory that she just contributed 5 or so stand alone tracks 6 months prior to airing and they are squeezing them in wherever Go Shiina was like "whatever" during his filmscoring sessions.
Yes collaboration means that they re working together on something, like it happened with Revo and Kajiura on the dreamport single, but in here, they seem to each get some orders from the sound producer / director and working totally separately. That Homura awards ceremony was probably the first time they ever met lol
Similar thing happens with Kingdom Hearts soundtracks ever since others got involved in it besides Shimomura. I can tell apart the non-Shimomura ones right away and the quality drops significantly =_=. At least in KnY its not so obvious difference.