I'm not great with the lighting issues so I'll let someone else take that, but the pc might not penetrate the water enough to get to the nem which are usually bottom dwellers. I could be wrong though, it's happened before!
FWIW - crispas a generally sand dwelling anemones. Depending on how finicky the one you get is, it may not do well in the tank without the sand. These nems are usually poor shippers and come in VERY stressed and in need of some TLC. Not having the sand that it feels comfortable in may stress it even more. Just something to think about.
Good luck, and hopefully someone will post with better answers!