I got a reply a few days ago, after using the email. It was from Jim Sink. He said his associates would be sending me an NDA, but nothing yet. Hopefully soon. I'm very interested in their prices -- I'd love to make a whole region, complete with a game, but it obviously depends on how much these things will cost.
The email did hint at something like a small mainland: it mentioned a limited number of city blocks that they'd rent out to smaller creators after the launch. But mostly, they seem to be -- thankfully -- focusing on something like LL's private sims.
Rock, I don't know about their Casual Games API, but Lua is a scripting language used elsewhere. I've bookmarked a few guides to it, but haven't gotten far in any of them. None of them have knocked my socks off so far, either. Nonetheless:
Programming in Lua : contents Lua for Beginners lua-users wiki: Learning Lua