1. Use either HDMI(ARC) or connect an optical cable from the TV to the AVR.
2. Check TV's Owner's manual, but likely only stereo files will play.
3. See #2.
4. AFAIK, should be possible using Windows Media Player.
You can add another wireless router set to "bridge" mode to connect the 5008 wirelessly or use Powerline adapters. Also, the 5008 uses DTS Neo:6 while the DTS Neo;X on the 1223 simply adds one additional speaker.