What about the db references in the spfile when you want to rename the db? When running the create controlfile command I got this error:
ERROR at line 1:
ORA-01503: CREATE CONTROLFILE failed
ORA-01504: database name 'FOO1' does not match parameter db_name 'foo'

I created pfile from spfile, changed all db references there, and converted back to spfile.
Then it worked!

Somehow offtopic, but also edit name in /etc/oratab to reflect name change for dbca.