PyPy is doing really well on compatibility these days. It can use all the C libraries natively, and a lot of the speed issues there have been resolved.
Literally all of them, without any issues? I'm working on implementing support for Ruby's C extensions in an alternative implementation and it's a right slog.
PyPy dev here. Yes to both - all of them and it was a right slog. If it doesn’t work report an issue. We have a proposal looking for funding to make it fast.
Great! I appreciate you sharing this. I checked the PyPy main page, Downloads page, and Compatibility page and while I didn't look exhaustively, nothing mentioned 3.6 or 3.6 features.