When I was super-busy with my career, I frequently used my hand to face lather. You can manage a very decent lather with a good cream and some water on a well prepared face for shaving. I've used Cremo, Proraso, Nivea, Cella and Arko (cream). They all lather-up nicely with your hand in a pinch. You could do the same with soap, but it's just easier to build a lather on your face with a cream when you are hand lathering.
What I used to do was use my left hand for face lathering. I'm right handed, so I shaved with my right and held extra lather left over from my first shave for a 2nd lathering with my left hand. DE razor was the razor of choice for hand lathering for me because I need 2 hands for my straight razor. I can shave my whole face well with only my right hand with my DE.
Again, I didn't do this because I wanted to, I did it because I was pushed for time every morning trying to squeeze 25 hours into a 24 hour day. I hardly had time to shave, let alone use a brush and/or bowl for lathering.