I admit I saw these first and I ended up becoming confused about who the main character was due to the order that I watched. But after seeing the series, I find myself feeling attached to the characters since I know who they are and what they are fighting for.
Personally, I think it would be best to watch the series season 1 first so you know who the main character is and don't get confused about it, then you watch these prequels, then watch season 2.
Overall, a very good build-up to the first season's storyline! It made me want to continue to see what will happen until the end. I will not spoil anything, but hopefully, there will be a season 3 to finish the story and leave the characters with a very happy ending.