Can we filter reports to only show certain host names, or do we need to set these up as views?
There are no hostnames nor views in App+Web properties. All web-based traffic will come through as web data streams. You configure your streams in the Data Stream section of the settings. More about that here.
The equivalent of hostname is Stream Name, however, this is not available in the reporting configuration. To filter a report based on a unique stream, you will need to use Stream ID in the exploration report. See here for more detail.