Need to get first & last name on signup and into MailChimp

I'm reaching the end of my rope here trying to accomplish what seems to be a fairly basic need.

When members sign up, I would like to collect info about them:
- First name, last name, city, state

This info should be included in the remote ping to MailChimp list subscribe.

I read that in order to add fields to the signup form I should install BuddyPress... so I did that, and added the fields...

Question 1: How do I access the data from those fields for setting up the remote ping?

Honestly, including at least a first name in a mailing list signup seems to be a pretty basic requirement... what kind of marketer doesn't want to be able to address his or her email recipients by name?

Also, the BuddyPress info doesn't seem to sync with the WP profiles unless I associate it with the Register page. But when I do that, then Membership no longer shows the subscription plans on the register page.

Question 2: What is the correct way to set up BuddyPress and Membership so that they play nicely together?