Looks like Lucy was trying to get the other dog to play to me. Lucy was displaying swagger...C'mon other puppy dog lets play. Now if what you say the other dog let's Lucy know and both go back and forth in a growling and snapping at each other...then I would consider that aggressive. Watching Lucy run around trying to entice the other one to play. Again to me it looks like play.
Watching your video kind of made me cold looking at the snow. Hopefully, you will post warmer videos. I guess Wisconsin is like that in the Winter...you can have it.
I also will say thanks for your post.