OPU being front end? Are you sure? Fulfillment should own OPU up until they take it to the front, then the front end owns it. That's how it's described in all the guides/addendums I've seen. The front end gets hours for OPU, but that's for processing Pickups and delivering DriveUps that Fulfillment dropped off, not for picking anything.
It doesn't make sense to take anyone away from the front end, especially for doing fulfillment when we have an actual Fulfillment team. If anything, future plans put more front end work on their plate. They take over operator duty for the phones and advocates on empty checklanes are supposed to run over to the SD to help out if guests are waiting there.