The resource that is best to teach all of this is the resource called, "Get off your butt, step away from the computer, and go out and start doing things in the shop".
1) A general 80 degree turning tool
2) Use a grooving tool I guess.
3) I would not part this type of work off. I would turn the left hand end first, then turn it around and turn the taper end.
4) Run a test piece and send it to the heat treater and then measure the change for that batch of material. Each batch of material might be slightly different.
5) A grinding machine.
6) Clamp it in a vise with the OD flat on the bottom of the vise and cut the first notch. Flip it after deburring so that the first notch sits flat on the bottom of the vise.