Your easiest bet is to find a teardown video and pause when they have the case off.
The coil is the coil shaped bit in the black plastic on the left.
Technically, you could get one of those meters that measures the power draw of a device, hook it to a wireless charging puck and slide it around. The power draw will be higher the more closely aligned the two coils are.
Going that far is going to be really fiddly and probably not worth the trouble though.
You can vote from overseas in whatever location was your last permanent US residence.
People in DC get to vote for president because a special law was passed giving them electoral votes.
People in Puerto Rico have a US permeant residence that doesn’t let them vote for president, so they can’t legally vote from a different jurisdiction.
One of the proposals that’s come up occasionally is to make a similar law for Puerto Rico as we did for DC, but there’s never enough consensus on any plan to go forward, up until relatively recently.