Has anyone been successful at adding an accounts payable email, and sending statements to the accounts payable email instead of the main email on the account?

You can do it by workflow schedule or by button on customer record to send statement.

Is there an option or ability to do this from batch? Sorry not a super user, and still learning netsuite

You can do this in batch by going to Mass Update>Bulk Email. I would read up on this and/or test before trying it in prod though to make sure the emails are coming out how you expect.