Migrate EJBs, use DDConverter to migrate XML files. Upgrade JDK and compile against the new version. Compile against the new WL jars and use the new WL EJB compiler instead of the old one. Update your ant tasks if applicable.
mmm I have never done this, but have observed a similar Oracle migration.
Backup the database and restore it in the new table space
Migrate the plans
Ensure that all synonyms and configuration related params are migrated.
I cant think of anything else. I have done the WL migration but not the one with Oracle DB.