1. sounds like you need to amend your umask setting (e/tc/profile of /home/you/.bash_profile or .bashrc).
It's probably 022, try 002 and then logout completely.
2. Do you mean multiple users have the same numbers as each other and (separately) multiple groups have the same group id?
That's definitely not right, although the uids and grpids are in separate name (number) spaces, so a uid can be the same as a grpid (default in RH based systems).