I made a few changes to the Exemplar of Harmony and Paragon of Discord classes. I reduced the range of their harmony/discord feat ability to 100 feet per class level, I altered the Deceit Judgment, and I changed the Apathy Discord into the Betrayal Discord, as per Owrthro's insightful comments.

I think the classes are generic enough in ability and premise to be easily adapted to any number of high-level magical girls, with Madoka Magicka being the main inspiration and example.

I agree that creating a barrier as a swift action is a pretty powerful ability, even for Tier 3. Perhaps instead of actually creating a barrier, it could be an immediate action that does one of the following:
a) grant concealment to a single target against a single attack, or
b) grants temporary hit points equal to your Magical Girl level to a single target, but only against a single attack

You could create a level 2 or 3 Illumination that increased the benefits of the barrier to total concealment and maybe double the temporary hit points.

After all, barriers in Magical Girl shows tend to either deflect incoming blasts, or protect the user from harm until it's shattered. I think this would be a better alternative to creating an actual physical barrier, which would generally be more versatile and powerful.