What would be the max height a robot could be while in its loading zone?
I would assume 60" because you are outside of the team’s autozone.
Correct.
If you’re in the loading zone and still in contact with your pyramid or auto zone, you are WAY outside that 54" cylinder.
Not sure what the 54 cylinder has to do with it. 
Once no longer contacting your auto zone carpet you limited to 60". Your loading zone is a long ways from that.
That’s exactly his point. If you are somehow touching both the loading zone and your own auto zone/pyramid, you will have extended beyond the 54" cylinder.
If you are in your own loading zone you can extend to 84 inches
No you cannot.
If I’m wrong, please cite the rule.
While in yiur loading zone you can be a max a 60in. but if you are in your pyramid zone where your goals are you can go 84in.
3.2.5.1 G22
ROBOT height (as defined in relation to the ROBOT) must be restricted as follows during the MATCH:
A. If in contact with the carpet in its AUTO ZONE and/or its PYRAMID, 84 in.
B. Otherwise, 60 in.
Violation: FOUL. If continuous or repeated violations, TECHNICAL FOUL.
3.2.5.2 G23
A ROBOT’S horizontal dimensions may never exceed a 54 in. diameter vertical cylinder.
Violation: FOUL. If continuous or repeated violations, TECHNICAL FOUL.
Emphasis added.
There were some add-ons for G23 to address the cylinder relative to pyramid climbing, but the essence hasn’t changed.