We are actively investigating matchmaking issues on Xbox One. Until resolved, players may be unable to match into the Crucible or Strikes. Public spaces and the Tower may appear empty for some players.
There's normal and heroic. Heroic doubles the enemies and makes them way more agressive. It also drops better loot in my experience and gives a little more exp as well. I solo'd all heroic my first play through and it was fun and punishing.