They did not release a phone, they developed a custom Android skin that could be adopted by partner telcos.
They didn't. HTC is an independent company working as a business partner with Facebook. Just what Mark said.
Of course they did. If the leak didn't have some truth to it, he wouldn't have been so upset about the leak.
It's literally not a phone. Facebook didn't build or design any hardware. It's exactly what Mark said, an interface layer (Launcher) for Android, and it came bundled with this HTC phone.