I think that the OP is getting a hydraulic actuated rear blade.
As far as using only hydraulic rippers on a box blade, I'm guessing that the OP has not used a box blade much. You adjust the top link constantly when using a box blade, same goes for the side link if you are doing much grading at all.
One of the problems of getting a hydraulic tilt with-for a rear blade is you only get the tilt action for that one implement. If you go with a hydraulic tilt on the 3pt hitch, you then have that capability for all implements.
OP mentioned a PHD, don't you think that the auger ever needs to be plumbed up? The auger only swings back and forth, not side-side. The down pressure cylinder is mounted on the PHD, not the tractor and it is a single acting cylinder only.
Also depending on how rough your terrain is, but it is common to use a hydraulic top link when mowing and have it in the float mode while doing so. If the ground is hilly the mower will not move enough and the wheel ends up in the air. Put a hydraulic top link in float mode and the mower always follows the terrain.
So even using your own listed usage, a top & tilt set would be beneficial.
OP, do yourself a favor and get all 3 rear remotes and at least one of them with the float feature. I would get 2 with the float feature myself.
Good luck with your decisions.