Pretty sure the only 8-bit weapon you get for free is Link's (there are others, such as Sheik using an 8-bit Ladder as a harp, or Ghirahim and Fi using 8-bit Arrows as their wepaons, that are only in the DLC), and while Cia, Wizzro, and Volga are playable for free, their story episodes (and their L2 and L3 weapons) are only in the Master Quest DLC.
And the Master Quest Adventure Map does follow game history; it's the same map as the original game's 2nd Quest. And though that was, in appearance, the same as the 1st Quest, a lot of things were moved around and changed, which the MQ Map does as well. It's designed to be the 2nd Quest of the main Adventure Mode map, which makes sense seeing as 2nd Quest was the original Master Quest.
Oh and the new Adventure Mode maps include more hearts for each character, bumping the maximum from 30 to 35. Presumably the Adventure Mode map coming with with Twilight Princess pack will bring 5 more for everyone, maxing out at 40, while the Adventure Mode map coming with the Majora's Mask pack will bring another 5, maxing out at 45 for each, or 3 complete rows of hearts.