1. 2. Every profile is its own unique sandboxed area supposedly. So if you decide to use a VPN each profile links to your VPN provider as its own new device. Thus having two connections with mullvad creates two separate devices for each profile. Running a VPN is always a better method to browse besides the security and privacy aspect. That being said. I would switch servers once your done with your own personal accounts for whatever apps you use which are each sandboxed BTW by default. Side profiles do not unless you select the setting run in the background. Consumes a lot of battery. But the main profile does. So switching back to owner from secondary profile your still connected to VPN inside owner. It doesn't drop the owner profile connection because owner is always running. Its the anchor for the OS IME.
2. I haven't found a reliable way to transfer photos other than flash drive with adapter or Bluetooth to PC then Bluetooth back. I'm all ears on this one. I've even text them to myself which for privacy is not a good option.

Edit account to profile. Doing to done.