SSL is included free and no IP address is required. You don't need to buy your own SSL.

We install the SSL for you when you signup.

SSL is standard. To use SSL you simply put "https" into the web browser or set Wordpress admin site domain to "https", instead of "http".

SSL works only with your domain name. It is not shared with ours or any other domain name. And it is auto renewed only for your domain name.

The IP address is shared as normal but the SSL is not effected in anyway by that. If you really do want your own IP address for a specific reason, they are $50 per year.