Would it be possible to show information from the Ticketing App in Visual Overview or in a Dashboard? Not with an embedded webpage, or by creating a driver which then interfaces with the Ticketing App. But being able to fill a drop-down with all active tickets, and then being able to select more details of that specific ticket.
This isn't supported out of the box by the Visual Overview. You have already listed both alternatives that are currently possible (embedding the ticketing app or doing a workaround in a driver).
The dashboards app currently does not contain any component that can display a ticket, nor does it have ticketing data available as a data source.