When you installed Simple Chat Colors did you also install Simple Chat Processor? Personally, I have not used them but I do believe that they both have to be installed for it to work.
As for your second question, yes it is possible.
SourceMod Library has functions that allow you give weapons with specific ammo amounts ( primary ( in clip ) and secondary ( in reserve ).
*Edit*
If Simple Chat Colors still does not work, this might:
https://forums.alliedmods.net/showthread.php?p=1756508 . You can edit it yourself or have someone else edit it. It would be very simple: for your groups find a specific flag that the lower groups do not, and set it up as that. You can change the color of the tag, the players name, and the message itself. Good luck and have fun!