Charging 7390 via powerbank and some other basic questions?

 Hello,

I'm new the XPS series. Got 13 inches-7390 with non-touch display model. Could you help me for following:

1. Wich portable powerbank do you recommend to use with this machine? It seems that I have to a PD cable as well.
2. Does the XPS 13 comes with stereo built-in microphones?
3. Is it possible to use face detection to sign-in to Windows instead of fingerprint?

Thank you.