1. Data share between AAM and Google/FB involves a unique identifier at both ends which in general scenario is the deviceID. for AAM, it is AAM ID and similarly for Google/Facebook it is this Id which gets identified. As customerIds are linked with AAMUUID only, using this information a unique customer can be identified.
2. For ITP2, currently, Audience Manager team is evaluating workarounds for current and anticipated tracking prevention announcements. In the immediate term, we’re working on a scalable solution to capture full referer URL data for all customers. Further out, we’re exploring ways to leverage first-party cookies to track Safari users.
For more information about user identification in two systems, please follow this document.
The Google/FB pixel call is an async call which is enabled in the audience manager backend which your audience manager consultant and client care will be able to add. There are no other changes required to make sure the order in which the pixel/id sync fires and audience manager code takes care of that.