Simply use this command to get package name:
aapt dump badging {apk-file.apk} | grep package | awk '{print $2}' | sed s/name=//g | sed s/\'//g
Getting main (launcher) activity is similar:
aapt dump badging {apk-file.apk} | grep launchable-activity: | awk '{print $2}' | sed s/name=//g | sed s/\'//g