120 is more than sufficient to start you into Heavensward content. In fact, the first few Heavensward quests will literally throw HQ level 115 gear at you, and the game will continue to throw relevant gear at you up to 60, nevermind dungeon drops.

The accessories you are confused about from a vendor are tradeable from Amber, which are rare treasure drops that you can find in the new Levequests. A normal Levequest chest will contain one; a "large-scale" levequest (costing 10 leves) will have a full set of 5 if you get lucky and find a chest.