The first one isn't so simple since any code loaded into the browser can access the audio capabilities of the system. It is possible to isolate running instances of plugins, but don't expect anything like Windows' per-application audio settings. Maybe
make a proposal to the maintainers of the NS plugin API?
The second one seems doable, but might fall victim to the same problem that Excel has when you tell it to work with "web data": the structure of a page is volatile. That's why RSS is so popular for syndication.