I’m going to upgrade from 11i to R12 soon. Can I deploy Application Auditor before the upgrade, and if I do, are there any special considerations?

There are no special considerations with deploying AA on the database for your 11i or R12 environment, or for when you upgrade from 11i to R12.  There may be situations where you need to recompile or reconfigure the audit configurations or transport them from one EBS database instance to another.  AA’s user interface supports these compilation, configuration, and transport activities.