With Verizon, the carrier lock is on the phones for 60 days before it is removed. Your best bet may be waiting until the lock comes off. The person probably bought it from VZW and sold it as unlocked.

Most annoying thing about going from Android to iOS was dealing with my photos and videos. They were not stored locally but on Google Photos. You can use Google Photos on iPhone but having them stored locally and on iCloud is just top notch. But downloading them all took time and data, and after that I'm never switching again lol.