Fair enough. I'll farm a couple of these. I think we're just very used to Enix's regular events where you get everything in 20 minutes, but considering most of these are available items or just earrings it's not that unreasonable they don't just hand them all out. It's like they've added bonus rewards to dungeons for a month.

Irregular tomestones of philosophy will not be awarded under the following conditions:
・Joining a Party in Progress
Is it just me or is this unnecessary though? If someone leaves your group you're in trouble.