If you're catching a late nightbus, there's a cafe and bakery to the rear of the terminal on the ground floor called Sawamura which is open till 3am and is pretty relaxed about people eating slowly!
A brilliant demonstration of Japanese efficiency... Excellent signage and directions, connected to the JR station and NeWoMan. Uber convenient to get to/from Haneda
The staff at the ticket counters are very helpful. You’ll be able to get a bus schedule from them here. Payment for tix can be made by cash or credit card.