Yes, you need to pay out your contract if you cancel your service with Telus earlier.

If you are planning to port out to Koodo, do not cancel your service with Telus. Once you receive the SIM card in the mail, you can start the porting process. Your existing service with Telus will automatically be cancelled once you have successfully transferred over to Koodo. Should you cancel before the port transfer, you risk losing your existing number. 

As for the Apple Watch, you cannot use it on a data plan, but it should still work if you are using wifi on the watch and setting your personal hotspot on your phone. 

Thanks! Is it possible to keep my apple watch plan with Telus and have a new Koodo account/plan for my phone?

I don't think it would be fully compatible if your Apple Watch has a different plan than your phone, but you may give it a try. That said, you can still use it similarly to the GPS model.

No, this won't work. The apple watch gets linked to the phone/phone plan on your telus account. As soon as you remove your phone line, it wouldn't work.

That being said, as long as you always have your phone within Bluetooth range of your watch it'll function the exact same. You only need cellular if you're away from your phone.

Thanks for all the info! I switched over today :)

Oh and if you setup WiFi calling, once à call is made, you can still make calls via WiFi without your phone connected to your watch.