Unfortunately, there is no way to control ordering or the result. As the layers in ArcGIS Online reference web services, we're dependent on the speed of the response of a given server and display the first response first (thus, there is no ordering of results across multiple layers). There also isn't a way to specify a sort order for a given layer. There are no current plans to change this behavior.
In your second question, do you want all the results to display in the popup at once and then you could pick one to examine it further, like ArcMap Identify? This is not possible either.
Mike