One good thing (maybe, I haven't actually read it) from watching the WAMS/Bili story is the introduction to Frans de Waal. WAMS actually encouraged their followers to approach him for expert opinion, but I don't think he replied. I din't think they realised either, he is fully supportive of zoos. ‘I Cannot Name Any Emotion That Is Uniquely Human.’
His earlier work 'Chimpanzee Politics' was written about the newly-formed Common Chimpanzee colony at Arnhem Zoo in the 1970's. There are descriptions of how they introduced adult males to a larger group of established females, by removing the two top ranking females for several months to allow the males to gain power. Similar method that I think Wuppertal are now employing to ease Bili into their group.
...and I'm sure he wouldn't have advocated giving up on Bili's introduction or removing him to live in isolation with WAMS either...
He didn't. A lady in the US says she was in conversation with him and he agreed to talk to Zoo Wuppertal about the situation. She did not come back with any updates as far as we could see, but another follower of WAMS later said he would contact him, again with no obvious reply. We ourselves then posted on his facebook asking for an opinion, which WAMS took great exception to, regardless of how neutral our post was.