I believe the E should go down to at least 1200 agl and the airspace should follow proven international practice for low level class E.
Without the time to phone experienced controllers in Canada or the US I cannot confirm exactly how it should be done. I would follow advice from the experts in this field.
Yes, the controllers would have to be approach rated.
On those US figures it looks as if we are at least 100 controllers understaffed. The US has about 15 times the population and about 15 times the number of aircraft.