Travelling when AP extension in progress

[Shanaz]

My GC is filed in EB1 category. I-485 is currently in progress. I-140 approved and my current EAD/AP expires on 3^rd December 2016. I have applied for AP/EAD extension which is in progress  (USCIS received date per the notice is 6^th September) . I absolutely need to travel to Canada for few days (to complete my Canada PR landing) and I need to travel before 13th December 2016. 

A. Is it ok to travel to Canada and return using my current valid EAD/AP which is expiring on 3^rd December 2016 - while my EAD/AP extension is in progress? would it cause any issue ti the extension if i travel out of US 

OR

B. Should I wait till i get the extension and then travel on the extended AP. My worry here is if I do not get the extension before 3rd December 2016, then I wont be able to travel to Canada until the EAD/AP extension comes through. Is there chance for AP extension to be processed more than 3 months?