Insert multiple HTTP header variables

You are doing sideband with an iRule. Basically you should be able to parse the sideband response for the cookies and headers into local variables. And then insert them to the request to the server. There are multiple threads on DevCentral on how to insert/replace/set headers and cookies.

Have you looked onto Mark's HTTP Super SIDEBAND Requestor (https://devcentral.f5.com/wiki/iRules.HTTP-Super-SIDEBAND-Requestor-Client-Handles-Redirects-Cookies-Chunked-Transfer-APM-Access-etc.ashx)

The sideband call is a proc call within an iRule. It can return cookies and headers as lists, which you can the search/parse for intended headers, and then add them to the request or redirect. There is an example of adding cookies into an redirect response to the client (with APM event in this case).