Re: Pulling Eggs
I don't leave my tads in the dish on purpose, but I only check on them every other day when I feed, so they could be in there for up to 2 days just based on the rhythm of how I do things. I don't keep much water in with the eggs, so it isn't probably good for my tads to have to hang in that little water depth for all that long. I will pull them immediately if I see that they have hatched. I feed them a little bit right away, but Josh's is probably right that they aren't real hungry right away because they have been metabolizing their tail.
You will find a lot of opinions on whether to do water changes or not. I tend not to do them unless the cup looks especially foul. Opinions vary a lot on this, but my experience has been that tads seem very resistant to nitrogen and other by-products that build-up over the course of the aquatic phase of the morphing process. One other thing that you didn't mention but that probably should be addressed in this context is tadpole tea/adding leaves to the water. I only do this for terrestrial species like Dendrobates (the genus), but some folks do it for all of their tads. Especially for Ranitomeya, my reasoning is that if you are laying in broms for the most part, the water is probably getting flushed regularly by rainwater. Again, other people may have different opinions.