Yes you can record in-game activities, but there has to be an element of yourself doing real life activities as well with the logo somewhere in the video.
Yes you can use whatever program you would like to put the video together, and it doesn't have to be all in one go.
We will know who is trying to take credit for someone else's video, so don't do it. Be sure to write your character ID in the information/description portion, or better yet, show us your character ID in the actual video. Do what you can to authenticate that your video is yours.
imSOsleepy, you won't need to make another video. I see your character ID in your submission.