Best way to add a "buy now" button to a sales page and then drip content

Hi,

I have a sales page created and would like to offer a 30-day membership to the course it's selling.

1) How can I add a "buy now" button on that page? (i.e. instead of just having the built-in "register" page that lists all of the membership options)

2) Upon registration I would like to have members redirected to a specific page that they now have access to - is this possible?

3) I have set up dripped content for this membership and would like to add members to a Mailchimp list that reminds them when new content is available. How can I sync with Mailchimp?

Sorry - lots of questions. I appreciate your help!