Since all of our creatures except for Hinterland Sanctifier are legendary, if we can get some counters on Aerith and then have it die (which we can do by playing a second copy thanks to the legend rule), our team will get massive, maybe big enough to win with just one attack
Coveted Jewel There are more busted cards I can copy with Mishra, Eminent One, but if I do that once with Coveted Jewel, I draw six cards for neutral mana in a deck that usually has a Slobad, Iron Goblin effect lurking around
Marcy: More for the cool art, but FF games are (traditionally) turn based RPGs, and this recreates a battle from FFVI, the game that really put FF on a lot of people's radars
For actual discard this card is one of the weaker effects on the list but the combined package is so potent and versatile you just don't care
Toph, Earthbending Master and Wan Shi Tong, All Knowing both seem like particularly fun commanders to build around
Youre going to want to quest with this character since he can generate four lore by doing so