This should depend on whether your "chrome" package has the Widevine content decryption module plugin packed with it. With Arch linux - for example - it's a separate package to install.

Yes, Netflix and Widevine should work out of the box if you are using Google's Chrome or Mozilla's Firefox builds for Linux.

Yes, it works fine with Firefox. I looked up for Widevine in Synaptic and found nothing. Same thing with Chromium extensions. I'll keep researching.

It works for me, but only on normal mode. It won't work for me on incognito mode.