Tablet would be way too slow. Is there even a video editing app for Android?
Yes, several, but most of the ones I've tried are lacking in one way or another. KineMix is a free app that allows you to splice together footage (you can set the the start and end points of each clip), with no re-encoding being done (I've even been able to do this on 4k footage from my GH4). You can add audio as well. I've also tried VideoShow and several other editing apps (search video editing apps on Android). Haven't found anything that really impressed me yet.