The torn WiFi cable will not keep the digitizer from working correctly. The main thing on the iPad 2 is to ensure the two small clips that secure the connector are not damaged and the cable is folded under the edge of the frame correctly. I've done probably about 100 iPad 2 digitizer replacements and I can say the cable is certainly a little bit susceptible to damaged if not installed correctly.
If you pop up the two clips and slide the very edge of the new digitizer flex cable into the slots, then use a spudger or edge of a credit card to push them into the connecter nice and snug. Do this gently so the cable doesn't try and bend upwards or jolt in one direction as this can definitely damage the cable and make it have dead spots in the screen.
If either of the two clips are broken this will not allow the proper pressure to be put down onto the connector and it wont work correctly. You can cut a small piece of mylar off of the old connector and use it as a wedge to stick on top of the connector and nudge it into place with a spudger, plastic pry tool or edge of a credit card as well to equal out the pressure and get it working. Its a little tricky to get it right but take your time and cut it to the perfect size and it will work. I've had to do it once when a connector broke. I've popped tons of those the same way and never had an issue but sometimes one will break.
Hope this helps man....
iPad 2 can be very tricky to do perfectly the first time around. And even someone like me who has done tons of them, its still something you gotta take your time on. Commonly I see people I am training try and get in a hurry or get flustered and make more and more mistakes as they go. An experienced tech like me will still take an hour to do the job. Thats mostly work, but I also just go slow and keep an eye on everything the first time, So if something isnt perfect you can correct it before you seal it back up and lay the fresh adhesive.