A
The update will always come from the carrier who the phone was originally locked to. The current carrier doesn't matter.The upgrade would go through straight talk. Verizon has no way if pushing the update to you since you don't have their service.
I just got off the phone with Verizon and the said straight talk would send it out.
They're wrong.
Possibly. It wouldn't be the first time I received a wrong answer from the tech support.