Google excluding site for queries for its exact name
So after banging our heads off the wall on this one for several more days, we posted in the Google Product forums: https://productforums.google.com/forum/#!category-topic/webmasters/crawling-indexing--ranking/fFo28LFajWo. Within 24 hours the site was appearing in results as expected, so it appears that Google must have manually intervened somehow, because we had taken every action that we could think of up until that point.
This site was a temp page for quite a while prior to the main site being launched, so I'm wondering if it somehow was affected by the domain temp page issue that Matt Cutts acknowledged several months ago.
In any case, if you have an issue like this and you have tried every tool available (sitemap.xml, requested reindexing, no issues reported in Webmaster Tools, robots.txt looks good, etc) then consider asking Google, apparently it does work sometimes!