Cannot run the template in .dbt extension in Oracle 12c DBCA

Since you asked RAC, please see if you can use this non-RAC example as a starting point. For db_name != db_unique_name != sid - Non-RAC - Oracle 12.1 - Custom Database (not seed)

On the command line, set ddbname == parameter db_unique_name, and also set parameter db_name

dbca    \
-silent \
-createDatabase \
-templateName    wailua.dbt     \
-sid wailua20           \
-gdbname wailuaq        \
-initParams db_unique_name=wailuaq,db_name=wailua       \

where wailua.dbt is copied from New_Database.dbt

db_name and db_unique_name are not mentioned in wailua.dbt

Note that variables SID and DB_UNIQUE_NAME expand in the template.

[oracle@waipio1 wailua20 templates]$ echo $ORACLE_SID
wailua20

[oracle@waipio1 wailua20 templates]$ sqlplus / as sysdba

SQL*Plus: Release 12.1.0.1.0 Production on Wed Jun 11 00:48:22 2014

Copyright (c) 1982, 2013, Oracle.  All rights reserved.


Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production
With the Partitioning, Automatic Storage Management, OLAP, Advanced Analytics
and Real Application Testing options

SQL> show parameter db_name

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_name                              string      wailua
SQL> show parameter db_unique_name

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_unique_name                       string      wailuaq

oratab:
wailua20:/app/oracle/product/12.1.0/db_1:N:         # line added by Agent

ASM:
asmcmd ls data/WAILUAQ/
CONTROLFILE/
DATAFILE/
ONLINELOG/
PARAMETERFILE/
TEMPFILE/
spfilewailua20.ora

Full crdb.wailua.ksh dbca script: http://pastebin.com/vx3k5g3U/

dbca log: http://pastebin.com/8UQDEDZn/

Even if you manage to create a database with nls_comp=LINGUISTIC, nls_sort=BINARY_CI (from scratch (Custom Database or manually), not seed or template) , the indexes will be still created without these settings and you have to take specify them manually.

SQL> select * from NLS_DATABASE_PARAMETERS where parameter in ('NLS_COMP', 'NLS_SORT');

PARAMETER       VALUE
--------------- ---------------
NLS_COMP        LINGUISTIC
NLS_SORT        BINARY_CI

SQL> select * from NLS_INSTANCE_PARAMETERS where parameter in ('NLS_COMP', 'NLS_SORT');

PARAMETER       VALUE
--------------- ---------------
NLS_SORT        BINARY_CI
NLS_COMP        LINGUISTIC

SQL> create table t1(id varchar2(1), something char(2000));

Table created.

SQL> insert into t1 select 'a', 'a' from dual connect by level <= 10000;

10000 rows created.

SQL> insert into t1 values ('b', 'b');

1 row created.

SQL> commit;

Commit complete.

SQL> create index t1_i1 on t1(id);

Index created.

SQL> exec dbms_stats.gather_table_stats(user, 'T1', cascade=>true, estimate_percent=>100, method_opt=>'for all columns size auto for columns id size 2');

PL/SQL procedure successfully completed.

SQL> select /*+ index(t1 t1_i1) */ count(*) from t1 where id = 'B';

  COUNT(*)
----------
         1

SQL> select * from table(dbms_xplan.display_cursor);

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SQL_ID  34cypvvhnwczh, child number 0
-------------------------------------
select /*+ index(t1 t1_i1) */ count(*) from t1 where id = 'B'

Plan hash value: 3724264953

---------------------------------------------------------------------------
| Id  | Operation          | Name | Rows  | Bytes | Cost (%CPU)| Time     |
---------------------------------------------------------------------------
|   0 | SELECT STATEMENT   |      |       |       |   907 (100)|          |
|   1 |  SORT AGGREGATE    |      |     1 |     2 |            |          |
|*  2 |   TABLE ACCESS FULL| T1   |  5001 | 10002 |   907   (1)| 00:00:01 |
---------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   2 - filter(NLSSORT("ID",'nls_sort=''BINARY_CI''')=HEXTORAW('6200'))

Index can not be used, hint does not help, and the estimated cardinality is just simply CEIL (NUM_ROWS / NUM_DISTINCT). This time with the proper index:

SQL> create index t1_i2 on t1(NLSSORT("ID",'nls_sort=''BINARY_CI'''));

Index created.

SQL> exec dbms_stats.gather_table_stats(user, 'T1', cascade=>true, estimate_percent=>100, method_opt=>'for all columns size auto for columns id size 2, SYS_NC00003$ size 2');

PL/SQL procedure successfully completed.

SQL> select count(*) from t1 where id = 'B';

  COUNT(*)
----------
         1

SQL> select * from table(dbms_xplan.display_cursor);

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SQL_ID  9pvkbfkycz6q4, child number 0
-------------------------------------
select count(*) from t1 where id = 'B'

Plan hash value: 3225262789

---------------------------------------------------------------------------
| Id  | Operation         | Name  | Rows  | Bytes | Cost (%CPU)| Time     |
---------------------------------------------------------------------------
|   0 | SELECT STATEMENT  |       |       |       |     1 (100)|          |
|   1 |  SORT AGGREGATE   |       |     1 |     3 |            |          |
|*  2 |   INDEX RANGE SCAN| T1_I2 |     1 |     3 |     1   (0)| 00:00:01 |
---------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   2 - access("T1"."SYS_NC00003$"=HEXTORAW('6200'))