Because the city defenses are down, creatures such as the antlions will no doubt be quite common in City 17. As usual the combine focus on killing the bigger beasts before shooting on you, so some kind of co-operation will no doubt be in the game. Whether it will extend any further than that...
At first, that same page showed almost the same info as the coming soon screen (info wait), albeit with a preloading button and a changed release date.
A good idea is luring those green ghosts out to town guards, that's how I beat the haunted boat quest in Anvil. As for the Forlorn Watchman, lure the ghost out of the ship and then attack and retreat... it moves so slowly you'll easily beat it.