Streamed data includes only user visits, user actions and client errors.
Not sure about the alternate but you can check the below listener plugin for the Real Time Business Transaction Data Feed. It allows you to easily get LIVE metrics from Dynatrace.
As Babar indicated the Purelytics stream only includes UEM data, and the Business Transaction Feed will let you send out data from your defined business transactions but this will only ever include PurePath level data - you won't be able to get host or process health metrics into a business transaction.
The only option I can think of is to pull the data you want using the rest interface against some dashboards you would create and parsing those, I don't think you'll be able to push this data out to other systems using anything built in.
I've never done this so I can't provide much help in implementation if you do explore that route.