As it turned out, my Surface Book was defective. When the lid was closed, the screen never came back without a hard reset. The computer was actually awake, the screen just didn't work.
After being hung up on twice when calling support (2 hours wasted) and then going through chat support (another hour), and following their proposed remedies (2 hours), I finally went into a MS store and they swapped it out for a new one (30 min + getting there).
I am happy with the solution, but boy was it aggravating to get it resolved. I highly recommend skipping phone support if you want anything other than basic help with the computer, they literally hang up on you The store people confirmed they are having trouble with the phone people and advise everyone to just go into the stores.
Anyway, thought I'd share in case someone has the same problem as me. As it turns out, sleep/wake was working perfectly...