I've yet to check out the OP's extension, but I've used a Firefox extension called LeechBlock before which (with some creativity) can achieve your bullet points as well. For the first I would set up one blocking profile to apply through early morning and a different profile (with the same sites) for the rest of the day; for the second LeechBlock lets you put a countdown timer in the corner of the screen so that at all times you know how much time you have left; for the third it lets you set up an "Override" which will resume blocking after a certain amount of time.

(Sorry if this is distracting from the OP, I aim not to shill but to help more people make use of productivity tools in this era of endless distraction.)