Hi everyone! My name is Hallie, and I’m a Program Manager on our CXM Team here at HubSpot. I connected with our product team regarding this request and they are marking this as Delivered, because most of this request has been solved between User Working Hours and User Working Hours in Help Desk and Out of Office settings, as well as Scheduled Hours for SLAs in Help Desk and Scheduled Hours for SLAs in Conversations. 
The part of this feature request that hasn’t been solved for is an auto-resopnder when all reps are OOO, but that is its own feature request here. We recommend leaving feedback on that post if that part is still something you are interested in! Any updates around that will be shared directly on that post moving forward.