Yeah, it's crap that they didn't give you guidance, although it seems like you managed to find plenty of issues quickly so perhaps the guidance is less necessary than it might seem.

Ultimately you know your extension, codebase, and use-case, far better than Google does, so it may not really be possible for them to give you the detail that you're looking for – you may be the only person who can do that.

I hope that they provide the support you need in understanding the problem to the point where the extension can continue to live on the Chrome store.