I can answer your first question. There is a limit of 50 headstones. I'm sorry I can't answer the second one. I don't have an Ipod, but the headstone limit is the same as the windows version.
EDIT: I found the answer to the second one:
Welcome, and we're glad you like the game!!!
The maximum population for the iPhone version of VV2 is 40 villagers. If twins or triplets are born when the population is near the maximum, you can get up to 42 villagers. The messages from the desktop versions mentioning a population bonus were inadvertently left in and will be removed in the next game update.
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this topic.
The max EE limit is 50.