Glory of the Hellfire Raider at 120

Now that my hunter has reached his potential max for the patch, I've decided to start running him through legacy raids for gold and glory. Last night I decided to take on Hellfire Citadel to see what he was possible of doing.

At the moment, Erlenmyer is level 120, sporting ilevel 378 gear. He has managed to pick up two 385 azerite pieces and fully populated all traits, giving him two 390 slot items.

During the first solo pass, he was able to complete the raid without any MAJOR issues. The only 'issue' was on the first boss (aka save the canons) fight. To win this fight, you must run waves of ammunition off the incoming tanks to the canons that the Kirin Tor have captured. Picking up the ammo box gives a short run speed buff to get you up to the canon and back. During that time, it's likely that another wave of trash has come in. I tried to do both during the fight (kill trash and run ammo boxes). After several waves, they simply stopped coming. I was able to run all of the ammo boxes then and finish the fight.. (new idea for soloing the first achievement)

As of January 8th 2019

As of this morning, here are the achievements that I was able to complete. 

blue = AOE all targets while standing here for Nearly Indestructible
black = barrage kills add here for Turning Tide.

1. Hellfire Assault: Nearly Indestructible -  If my experience last night is typical, a solo (ranged DPS) player should be able to sit between the two canons, kill all the trash (not running ammo) for a few minutes and run the ammo boxes AFTER the trash quit spawning. I'll try this again on Normal mode another night this week. (7.3.5 comment)
2. Iron Reaver: Turning the Tide - Dismiss (or pacify) pet. Aggro boss then un-target (so as to not auto-shot). Run over to a side of the arena (near black swirls on the image above). Wait for [barrage]. I had to repeat this about 6 times as the barrage only kills one or two at a time.
3. Kormrok: Waves Came Crashing Down All Around - Burn down the boss as fast as possible.
4. Hellfire High Council: Don't Fear the Reaper - Burn down all three (AOE) fast. I failed because I focus killed the first too fast and failed to AOE the next two in time. 
5. Kilrogg Deadeye: A Race Against Slime - Burn down the boss as fast as possible.
6. Gorefiend: Get In My Belly - Going to require two people (one who can kill self and one who can b-rez). ?? All the comments seem to indicate that someone has to be dead to enter the boss. 
7. Shadow-lord Iskar: Pro Toss - Burn down the boss as fast as possible - he still appeared to go through his next phase but got the achievement when all the trash was dead. 
8. Socrethar the Eternal: I'm a Soul Man - Didn't attempt, but it appears to require slowing the 'ghosts' so they don't touch you and explode. Kiting them long enough to allow 20 ghosts to spawn, then burn down ghosts before killing the boss.
9. Tyrant Velhari: Non-Lethal Enforcer - Burn down the boss before boss summons add. 
10. Xhul'horac: You Gotta Keep 'em Separated - Burn down the boss as fast as possible.
11. Fel Lord Zakuun: This Land Was Green and Good Until... - Burn down the boss as fast as possible.
12. Bad Manner(oth) - Failed because I decided to burn down even though I had a doom lord following me around. Killing the summoners clockwise from where you teleport in worked for this. DPS boss to 30% then stand in the middle of the platform so you don't get thrown off. The link points to a comment where they used a pet class to solo this. 
13. Echoes of Doomfire - Failed (I was tired and just wanted it to end), but (supposedly) it's as easy as "wait for doomfire to be cast, then kill boss" strategy. At 120, you can walk passed all his trash, and kill Archimonde directly. I had the party scene after boss fight with his 3 lieutenants still standing there.

As of Jan 9th, I am 7/13 completed. High Council, Manneroth and Archimonde should all be easy to solo. Socrethgar is going to require a bit of practice I believe. Assault and Gorefiend are probably going to require a group (can't get eaten and keep aggro also can't run boxes AND kill mobs as hunter or warlock). I'll post an update here when each is completed.

update night 1/9
Ran raid again on Normal. I completed two of the remaining six achievements. Reaper and Doomfire were as easy as stated. AOE down the council and wait for the first doomfire to be cast then kill him quickly.

Draenor has been freed but the legion is still hanging out.

• "#1-Nearly" I did what I mentioned and only dps during the first few minutes. When completed, I ran the ammo boxes (probably 5 or 6) to the canons and they blew open the door. From my sight, both canons didn't have a drop on health. Sadly the video I was recording crashed 3 bosses later and nothing was saved. So I can't go back and check.
• #6-Belly - There's no way to solo this that I can see. Normal I never got sucked in.
• #8 Socethar - mm, I think I need a class that has run speed. Druid or maybe shaman looks favorable. Those ghosts come out 6 at a time on normal mode. If any catch up with you, or run into any obstacle they despawn.  You need 20. Kill construct. Let him rebuild, don't kill ghost boss. While he's working he summons adds through 3 portals. One of those portals always has the ghosts. I could slow them, but could not outrun them. I believe he ran through the ghosts cycle about 3 times before hopping back into the construct.
• #12-Manneroth, I was trying to get him to 30%, then still had him targeted and auto-shot killed him.

Talking it over here in the office with a co-worker that he's currently leveling a VE hunter up to get the heritage armor appearance. As part of that build, he's running the [trailblazer] talent. This provides a 30% run speed increase when out of combat for 3 seconds. This has me thinking that about #1 and #8. Next reset (unless I want to try again on Mythic), I can test it again with this ability. Heck running old content with this talent may make all sorts of things better!