My question is, can I use Lu-chens support to add face down cards to my card pool and then when I use Schmetterling do I use the printed diff on the face down card or do they (like multiples) have 0,s for stats?

Was playing around with a legacy sakura and want to know if this works

Schmetterling refrences the stats of the card while in the card pool, so in this case, it'd be 0.

Okay. Hm well, I can still use it to clear my card pool while keeping my opponents clogged up

Thanks for the answer