A:AnswerYes. It'll work on anything that has a regular USB plug on one end. It's slightly larger than an iPhone. I have a few battery chargers and this is by far the smallest I own for how much power it holds.
A:AnswerIf charging from the battery power pack straight to GoPro Hero 6 you will likely wait around 4 hours from empty battery to full charge as the power pack only provides 1Amp voltage. On a full battery in a GoProHero 6 the power pack will keep the camera lasting over 24 hours recording and even longer if doing a time lapse.