Explanation
To configure your database for the Flashback Transaction feature, you or your database administrator must:
With the database mounted but not open, enable ARCHIVELOG:
ALTER DATABASE ARCHIVELOG;
Open at least one archive log:
ALTER SYSTEM ARCHIVE LOG CURRENT;
If not done, enable minimal and primary key supplemental logging:
ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;
ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (PRIMARY KEY) COLUMNS;
If you want to track foreign key dependencies, enable foreign key supplemental logging:
ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (FOREIGN KEY) COLUMNS;
References:
http://docs.oracle.com/cd/E11882_01/appdev.112/e41502/adfns_flashback.htm#ADFNS611

Explanation/Reference:
Explanation:
You must specify the names and locations of the seed's files in one of the following ways:
* (A) Oracle Managed Files
* (B) The SEED FILE_NAME_CONVERT Clause
* (C) The PDB_FILE_NAME_CONVERT Initialization Parameter

Note:
* In a container architecture, the parameters for PDB will inherit from the root database. That means if statistics_level=all in the root that will cascade to the PDB databases.
You can over ride this by using Alter system set, if that parameter is pdb modifiable, there is a new column in v$system_parameter for the same.

Explanation
Note:
Providing a UNIX Group Name
If you are installing a product on a UNIX system, the Installer will also prompt you to provide the name of the group which should own the base directory.
You must choose a UNIX group name which will have permissions to update, install, and deinstall Oracle software. Members of this group must have write permissions to the base directory chosen.
Only users who belong to this group are able to install or deinstall software on this machine.

A - OK
Start SQL*Plus and connect to the target database as the administrator who will transport the database with Data Pump import. This user must have DATAPUMP_IMP_FULL_DATABASE role to transport the database.
During the import operation, the database link must connect to a user on the source database with DATAPUMP_EXP_FULL_DATABASE role. The user on the source database cannot be a user with SYSDBA administrative privilege.
B - OK
Make all of the user-defined tablespaces in the database read-only.
D - OK
The source database and target database are running on the same platform with the same endianness.
http://docs.oracle.com/database/121/ADMIN/transport.htm#ADMIN13873