Am I correct on how Multiple Servers would function?

I'm debating going with the custom package, and here is what I want to do.

I set up an apache server on my PC. I set it up so that if you go to http://www.example.com you are directed to my music folder. I purchase and set up a Custom Dyndns package so that http://www.example.com goes to my machine. Assuming I follow the thinkgeek guides, this should all be great and wonderful, I can now access my music from anywhere. Lets assume I have all ports open, no antivirus or firewall, and the routers set to DMZ as well, just to make sure anything and everything is allowed in.

NOW. I love me some Minecraft. I set up a minecraft server on the same machine. If a friend attempts to join a game at http://www.example.com, will that work? Because its on a different port, will that route it to where it needs to be? I'm not clear if that is how this will work. If not, would I need to set up a subdomain, like http://www.minecraft.example.com and somehow tell the minecraft server... see, this is what I'm not sure of. If I decide I want to host files, a couple of game servers, lets throw some security camera's into the mix, is that all still going to be pointing to http://www.example.com, and each application works out what "server" software it is looking for?

Any help would be appreciated. I promise I have spend hours and hours attempting my own research before asking. :)

Thanks in advance!