Welcome to the community!
Technically, the Tablet plans are for eligible Fido post-paid mobile customers only (see here). While there have been instances where some customers were able to get those plans without a qualifying post-paid plan, I believe that they have closed many of the loopholes associated with that plan (see here).
I understand you have your internet with Fido. However, I do not believe that would qualify for a Tablet plan.
Hope this helps 😀