Would using dots and dashes (e.g. "ABC.Testing" or "ABC-Testing") in naming databases create any issues in the future?
Quoting objects in Oracle is generally a bad idea. That goes for databases, users, tables, etc. The only thing that should be case sensitive is a password, and that's only available in 11g and higher.
I realize this is just an opinion, but a lot of programs/users out there assume case-insensitive objects in oracle when developing their applications.
Are you talking about DB_NAME? You can't get that fancy with it, 8 characters long and limited special characters. Here is the official blurb from the Oracle documentation for 10g on DB_NAME parameter:
DB_NAME specifies a database identifier of up to 8 characters. This parameter must be specified and must correspond to the name specified in the CREATE DATABASE statement. ... The following characters are valid in a database name: alphanumeric characters, underscore (_), number sign (#), and dollar sign ($). No other characters are valid. Oracle removes double quotation marks before processing the database name. Therefore you cannot use double quotation marks to embed other characters in the name. The database name is case insensitive.
No one has followed this question yet.