Very interesting to see the differences. The places I've worked have used "Evacuate, Evacuate, Evacuate" and leave the direction up to the Flight Attendants. The thinking behind not giving a direction is that in many aircraft, my left is my in-charges right. Even though there should be a standard "left" and "right," it's a risk that need not be taken in a high risk, high stress environment such as an emergency. The same logic exists behind not calling "Remain Seated, Remain Seated," then calling for the evacuation; it sends mixed signals to the passengers, and in our manuals, "Remain Seated" advises the FA's to stop their silent review.
No right or wrong exists though, so long as both pilots and flight attendants are operating from the same playbook.
As for restrained passengers, here in Canada they get uncuffed, regardless of how bad they were. It falls under the human rights act, rather than any aviation regulation. Any person with a physical or mental impairment is assigned a Able Bodied Passenger if they don't already have an escort. Of course, that all goes out the window for an unplanned emergency.
