Yep. You can just disable filtering for specific devices. Or, if you want to get more granular, you can create device groups with different levels of filtering (including none).

My partner uses Facebook, I don't. Her phone has Facebook unblocked, but it's blocked on all our other devices.

As I recall, the answer is yes, as long as you make the Pi your DHCP provider or assign static IP. I was using it in the opposite way to block certain sites from certain devices. But my kids are old enough now that I haven't done it in a couple of years.