That model doesn't have a hydraulic clutch so there isn't any fluid to check ( just shared trans/ hydraulic fluid shared in the transmission. You may need to make an adjustment on the pedal. Follow the linkage from the pedal and there should be an adjustment for clutch engagement.
Not uncommon for the shifting/PTO issue. That model doesn't have a live PTO ( 2 stage clutch) A live PTO works with the use of a two-stage clutch. Pressing the clutch half-way will disengage the transmission while pressing it fully will disengage the transmission and the PTO. This allows the operator to slow down or change gears while the PTO is still operating.
An overrunning clutch is often needed with a transmission PTO. Without it, the driven equipment (such as mower blades) will put a force on the PTO shaft, and then the transmssion, due to inertia. The equipment will "drive" the tractor, and you will still move after using the tractor's transmission clutch. An overrunning clutch prevents this from happening by allowing the PTO shaft to freely spin in one direction. In more recent models, this is built into the tractor. In older tractors, it is an extra piece of equipment mounted on the PTO shaft.