Do I need to build separate data bridges for each tag I want to use in Mailchimp, such as "Active member," "Ticket Buyer last 6 months," and "educator"?

No, you do not need to build separate data bridges for each tag you want to use. Tags in Mailchimp are tied as attributes to a constituent's record in Altru. Adding or removing an attribute from Altru will automatically update the corresponding tag in Mailchimp. For more detailed information on how tags work with the Mailchimp and Data Bridge integration, you can refer to this article: How to use tags with Mailchimp