I use a hydration bladder all the time in my ULA Circuit. I don't tend to use the hydration sleeve, as I personally prefer to just put the bladder on top of stuff in the pack, but either options works fine. There is a little slot to thread the hose through.

In another entry you expressed a desire to do trips of up to 30 days. ULA is one of the most popular brands among long distance hikers, offering in my opinion a sort of 'sweet spot' balancing between weight, features, and durability. The circuit works well for me for long distance trips. With a heavier base weight and perhaps less experience starting out at least, the Catalyst might be a good choice.