Firstly, Mage of Heart Sanji is incredible. I'd always had him as a heart player (because fucking duh.) but the class was always shaky with him. Witch of Mind Franky is also perfect, he'd always been tough for me (despite him being one of my favorite characters). Though I personally always have Robin as a Mage rather than a Seer. I think her directly experiencing the darkness of humanity and the government that's swept under the rug provides great backing for that as well as, like you said, the Void Century shit. Usopp to me has always and will always be a Page of Rage considering in my eyes Rage is the aspect of Truth, Negative Emotions and Worship (shared theme with it's counter). Usopp throughout the entire series has told a lie, only for that lie to come true. From his army of 5,000 (The Grand Fleet) to fighting a giant goldfish (Little Garden), his constant lying founded in his fears and insecurity ends up coming to fruition. Also, the whole Perona "I'm always negative thing" is such strong proof that whatever he is, it's 10000000% either Doom or Rage. I ALSO WANT TO SEE USOPP IN TINY SHORTS