Confirming you will be just fine taking the bus to MK. And, it's better since the Monorail will require you to take a second monorail from TTC (as summerlvr noted).
As for the schedule, it is rare that they run all 5 hotels on one line. I stay at Epcot Resorts often, and I use the bus system to go to Epcot and Studios quite often (typically at Disney Springs hotels otherwise, so I pick up resort buses vs. direct-to-park buses often). The standard route is to have BW-Swan-Dolphin on one and YC-BC on another. During busy times (meaning both peak season and/or during morning opening or after park close), they will often put Boardwalk on its own, so you have 3 lines (BW, YC-BC, Swan-Dolphin). Only during very slow periods or in very unique circumstances have I seen them together.
Enjoy yourself!