I've had good luck with hosta that have an East exposure and shade during the afternoon. They get regular water, I do let the surface dry before watering again. Mine that have been established for a few years are just popping through the ground, so yours might still be waiting a bit. I'd give them at least a couple more weeks before giving up on 'em.

I've never had caladiums grow. I planted a bunch of them in my "shade bed" and they never even sprouted - I have a ligularia and a japanese painted fern back in the same area, and they do great there. I think I may have tried hosta back there too, and they didn't work - might be TOO shady there for some things.