No. The Oracle E-Business Suite database ORACLE_HOME cannot be shared between multiple EBS instances.
The Oracle E-Business Suite database ORACLE_HOME must be used exclusively for a single EBS database. It cannot be shared with other Oracle E-Business Suite instances or other applications. This applies to all EBS releases, including EBS 12.1 and 12.2.
Why does this restriction exist?
Configurations, log files, and more must be unique to a given instance. Existing tools are designed to work with the a single database associated with a single application. For example, the EBS pre-clone tool creates a clone directory that is related to a specific database. AutoConfig is designed to run for a particular application+database combination.
What are the support implications if you ignore this restriction?
Running these tools in an environment where multiple applications are associated with a single database ORACLE_HOME will have unpredictable results. If you report an issue whose root cause is found to be due to the sharing of a single database ORACLE_HOME between multiple EBS instances, our default recommendation would be to revert to a configuration where each EBS instance has its own database ORACLE_HOME.
Oracle will produce patches only for issues that can be reproduced in an environment where a single database ORACLE_HOME is associated with a single EBS application.