The additional shields could probably go in as bonus content? I mean, I'm cool with having it in there either way, because I'm a big fan of extra content.
Though as for the designs themselves? The Mirror Shield for what you having starting off is alright. I'm assuming you're just drafting a design, so I'm not gonna be too harsh on how it looks. If you took the outline from the black design and merged it with the Mirror Shield, that would be a good addition.
Can't wait to see further progress on the Mirror Shield!