Answer
Aurena expects a different URL parameter syntax than a plain OData-style $filter query string appended with '?' — use a semicolon before $filter instead of a question mark, and wrap the IEE field substitution in curly-braces-with-ampersand and single quotes, like ;$filter=Cf_Person_Id eq '{&PERSON_ID}' appended to the end of the Aurena URL. This specific syntax (semicolon-prefixed $filter, with the IEE field reference as '{&FIELD_NAME}') is what actually gets an IEE-triggered custom RMB to open a correctly pre-filtered Aurena page.