Seems a nice deal but you can try to negotiate a bit more.
You'll get MHL (Mobile High Definition Link) cable for playing contents from your phone on your TV.
You can also use WiFi to share contents, they call it Miracast, I think.
You'll also have TAG On for syncing your phone to TV but your phone needs to have NFC and TAG On app installed (or it should be a LG phone too ?)
Not sure about the audio-sync issue but you can always check the cable or try to update the firmware if that helps. Complaining also gets the job done
I don't think you'll need a dongle for the Magic Remote, everything will be provided with the TV if it calls for a dongle.
Enjoy your purchase !!