I want to update our auto-reply trigger, the Notify requester and CCs of received request trigger. Is there a way to include the body of the email that someone sends in that auto-reply back to them?
No, Zendesk's outbound email rules do not include a customer's message in the initial automated response sent to the customer.
This functionality can be targeted by spammers to pass their own messages through Zendesk systems to customers. For this reason, Zendesk implemented security measures to outbound email rules to guard against this behavior.
To learn more about these security measures, see the article: Understanding placeholder suppression rules.