In essence, an Important Affiliate links to a URL at a domain registered by Client. This URL redirects to a specific landing page for this Affiliate on Client's main domain. The landing page has URL /offer and has a CTA to Client's purchase funnel.
As the first URL redirects to the second URL, there is no referrer for GA.
Affiliate would like to see Google Analytics data relating to the traffic that Affiliate sends to Client - sessions, transactions, Goals (including entrances to purchase funnel). Client does not want to expose all Client's GA data to Affiliate.
What's the best way to provide such access?
I initially thought of Filters on a specific View for the Affiliate. But of the options that are available, I don't think any of them will help.