GHA Dungeon (Boss Skips / Glitches) : Archeage Submissions

Boss #1
Currently there is no known method to glitch/skip this boss.

Boss #2 (Glitches 2 and 3 interact differently depending on your team comp)
Glitch 1: Use "Play Instrument" during the bosses AoE Flame Attack to negate all damage.
Glitch 2: Long-range Archery can shoot the boss from the top level which will force the boss to run against a wall as long as that player can keep aggro. Basic Attacks by other players can slowly whittle the boss down.
Glitch 3: Have all players stand on the back-left ledge with the orange-colored vases on the VERY edge. Any time to boss does the jump attack the boss will fall back into the pit.

Boss #3
Glitch: All party members stand outside the boss room in the tunnel with the ramp, an Archer stands back about 20m from the doorway (up the ramp) and uses the skill "Missile Rain", if it hits the boss (AoE radius is kind of random) the boss will aggro and run at the doorway which seals shut. The Archer MUST stay in that spot but the other 4 players can Auto Attack through the door or use skills like Crows, Fire Rain, Meteor on the doorway to damage the boss.

Boss #4 (Mini-Boss)
Skip: The boss will not aggro if you hug the walls and you can sneak behind them without Stealth to open the door and skip this boss entirely.
Glitch: Using the Skip Method above. Kill the Medusa in the pit after the Boss, fill the water up and have someone pull the boss back into the water room. Stay in the center of the pool to keep the Boss on the ledge. Note: Sometimes the boss will jump into the water, stay on the ledges and out of melee range to avoid dying.

Boss #5
Glitch: Using a similar method to glitch Boss #3 - have an Archer use "Missile Rain" on the Boss while everyone stands at the doorway. The Archer must stand at the edge of the water and immediately drop into the water after aggroing the Boss. The Archer must stay in the water and not move or the Boss will reset. The Archer may shoot Missile Rain at the doorway while sitting in the water. Note: You may use most skills on this boss because it's head comes through the stone door.

Can anybody confirm?

Yes, well known so should be public but they are all regularly used so confirmed