See here https://en.forums.wordpress.com/topic/business-plan-plugins?replies=4#post-2964470
Yes to the ssl question.
We have 4 different plans: free, personal, premium and business. All hosting is free regardless of which plan you choose. You can view all wordpress.com plan features here https://wordpress.com/pricing/ Add a plan for each of your sites here: http://store.wordpress.com/plans/.
The Business upgrade includes:
• Google analytics
• Footer Credit Options https://en.support.wordpress.com/footer-credits/
• SEO Tools https://en.support.wordpress.com/seo-tools/
• The ability to install most plugins including woocommerce and the ability to install third party themes.
https://en.support.wordpress.com/plugins/ Scroll down to Business Plan Upgrades
WordPress.COM and WordPress.ORG are completely separate and have different username accounts, logins, features, run different versions of some themes with the same names, and have separate support documentation and separate support forums. Read the differences here http://en.support.wordpress.com/com-vs-org/