If they usually email, then email.
This will be an "interview" (it's like getting a driver's license). Your next step should be trying to appeal to CIC to speed up the landing so your kids' visas aren't required (that's just my opinion). Otherwise, just wait for Edmonton to schedule your landing.
Your spouse, kidlets, and yourself will all need to attend. Edmonton will give you instructions, but here is the address:
Edmonton
9700 Jasper Ave. NW, Suite 260
Canada Place
Edmonton, AB
T5J 4B8
They will ask you to confirm some details on your COPR's, after taking your (and your kids') passport(s). You confirm the details, answer a couple dead simple questions (don't lie -- they already know the answers), they will welcome you to Canada, and you will have a chance to ask any questions of them -- ask about the visa extension/refund.
You and your kids should get passport-sized photo's done. They are required for the PR Cards, and must be less than 1 year old -- in this case, that won't expire before landing.