I just recently installed my handlebar bag/rack/decaleur (Christmas present to myself) so I can’t report on how well it works IRL. The fit is good, and it seems solid enough in the shop. The Zao only works with a nitto pearl/technomic stem so you wouldn’t be able to use it. You’ll need to find something that works with a threadless stem.
Soma has two randonneur bars, one with an
ergo bend and one with a
round bend. The ergo bar has a flat spot where the curve is supposed to be on the drop. If you look closely at the side profile shot of both you will see the difference.
I don’t have any bikes with hydraulic brakes, but I have a few motorcycles that are almost 20 years old and the brakes are still fine with regular maintenance, so I wouldn’t worry about it. Even if they do fail on a brevet, it’s really unlikely that both brakes will fail at the same time, and you will be able to finish the ride with one brake. Everything I hate about my mechanical disk brakes, people tell me is solved with hydraulics, so that decision would be a no-brainer for me.