I have been through this a few times, and on a new site, Google and other SEs take their own sweet time to index everything anyway, and even more to establish rankings. So adding 100-200 pages right away should not be a major issue. There is no "penalty" or "sandbox" involved, just the normal delays in new content discovery, indexing and ranking at work, especially for new sites for which the SEs have not yet established a regular crawl schedule. Now if you all of a sudden add 100-200 IBLs, that would probably get their attention!

ps: When you add a REW integrated IDX, and even a few well-designed community search pages, you instantly get hundreds or even thousands of new pages. And when your local MLS gets 50-250 new listings a day, and drops 100-200 expired sold listings from the IDX feeds, those don't hurt either, and you have no control over any of that. The SEs simply add/delete the content as it happens, or 3-4 weeks after it happens, depending on how often it crawls your site.