The Y seats on the 787 will be narrower with slightly less legroom than in the 767 Y seats (which are refurbished seats that used to be used on the Qantas long haul routes)

The USB ports can’t just be placed anywhere WestJet wants, if they are placed by the knee area like on the 737s, then a completely new seatback would be required that would have to be certified for crash worthiness in respect to knee injury prevention. There probably isn’t even a seatback retrofit on the market that could be purchased, hence the position for the ports that had to be used, as they weren’t fitted to the seats when in Qantas service.