I like these sorts of busy images, so many details to spot. Shinmyoumaru's crab impression is excellent. As is Alice's awkward expression, which I trust is product of drink-bearing Marisa.
The simulation [of a beach] can take any form and be as subtle or as blatant as you like, but it must somehow clearly demonstrate its indoor nature.
If you can demonstrate what about those images makes them clearly indoors (and no, the Scarlet sisters being in daylight isn't good enough; that could just be artistic license), then go ahead and re-add them.