First, Telus, Rogers, Bell, Wind....all these carrier carry the same model of Note3 and running the same ROM
all you have to do is pull out your Wind sim card and do a factory reset. Then put in your Telus Sim card.
Phone will find Telus CSC setting and set it up as Telus phone.
As long your phone is sim unlock with Wind Mobile, any Canadian carrier should be working with your phone
About LTE, maybe there just don't have any LTE signal in the area, or your LTE setting has been turn off.
All you need to do is go into setting check under network and see if the phone is running GSM/CDMA/LTE or GSM/CDMA only, just switch between 2 and you will get your LTE with Telus LTE sim.
You don't have to worry about region code once your purchase unlocked online. region lock only apply when the phone never activate with local sim card and trying to activate with sim card from other countries. Just put in your Telus SIM and setting up the phone. Wind has this phone becuz it support AWS network, it doesn't mean the phone come with different modem!
Since you are not looking to root your phone or anything....there really no need for any flashing!