3rd party apps

Install the Digidesign Core Audio driver. I don't know about Toast and Jam, but it definitely works with iTunes and GarbageBand.

yes. Toast, Jam and iTunes all play through the Mbox output with the Digidesign Core Audio Driver (as long as ProTools is not open)

Once you have the coreaudio driver installed, you have to go into the configuration tool (in same folder as ProTools app) and add whatever applications you want to be aware of it. I don't think any of the apps you listed are in the default list, so they may appear to not work or not be able to access the Digi hardware.