1) Welcome to the Party!
2) As you are obviously new here, I have some suggestions to help us all help you:
When you post, please post your entire configuration including (but not limited to) your installation method and vicidial version with build.
This IS a requirement for posting along with reading the stickies (at the top of each forum) and the manager's manual (available on EFLO.net, both free and paid versions)
You should also post: Asterisk version, telephony hardware (model number is helpful here), cluster information if you have one, and whether any other software is installed in the box. If your installation method is "from scratch" you must post your operating system and should also post the .iso version from which you installed your original operating system. If your installation is "Hosted" list the site name of the host.
If this is a "Cloud" or "Virtual" server, please note the technology involved along with the version of that techology (ie: VMware Server Version 2.0.2). If it is not, merely stating the Motherboard model # and CPU would be helpful.
Similar to This:
Vicibox X.X from .iso | Vicidial X.X.X-XXX Build XXXXXX-XXXX | Asterisk X.X.X | Single Server | No Digium/Sangoma Hardware | No Extra Software After Installation | Intel DG35EC | Core2Quad Q6600
3) Goadmin version is useful, but not that much.
4) I'm not sure if a meetme room can be configured with custom audio at the moment of a new person arriving (to be played to the new person only)or not, but that's worth lookin into.
5) For inbound calls, the "ding" can be replaced with other audio and the wait time reduced which will cause the agent and the caller (both) to hear it. This is in the Modify Ingroup web page.
6) we've modified the "ding" for outbound to be heard ONLY by agents, but I suppose that same method could be used for "only" the client and a message!