The locationsRegion has a Point object:
${locationsRegion.point.latitude} latitude, ${locationsRegion.point.longitude} longitude
This represents the Southwest corner of the region around all of the locations in the map.

The locationsRegion also has east and north properties, which represent the amount of longitude and latitude in the region:
${locationsRegion.east} east, ${locationsRegion.north} north

To calculate the Northeast corner of the region containing all of the locations, just add the locationsRegion.east property to locationsRegion.point.longitude and locationsRegion.north to locationsRegion.point.latitude:
#set( $neLongitude = $locationsRegion.east + $locationsRegion.point.longitude ) #set( $neLatitude = $locationsRegion.north + $locationsRegion.point.latitude ) North east corner: ${neLatitude},${neLongitude}