Well, the three minibosses don't have any loot and have a third of Halion's HP, so I consider them minibosses and not real bosses, just like the three trees before Freya.
That's why I don't put them in the list, but gratz for any kill, Mini doesn't mean easy.
As for the trashes, you may want to bring a friend. Hodir? check. Yogg-Saron? check. The two storm guardians before Auriaya? Nope, I never manged to solo these

Turns out I just FD'd too late all the time. If you FD before the Scions enter combat they won't start chucking bolts at you, but once they do get in combat there's nothing you can do to stop them from killing you.

Now I just gotta beat the berserk timer :<

Are raid bosses from 60-80 content still thought to be calculated as your level +3, in terms of hit/resist/crit chance/etc.? I remember there being some debate about this in wrath, but I'm not sure if a conclusion was ever reached.

The answer is yes.

The level of the instance or surrounding mobs and nothing to do with the level of the boss mob you are targeting. All "Boss" mobs are 3 levels higher then players

Hunter Solo #Yogg-Saron : Two Lights in the Darkness# - YouTube <3

Killed Auriaya 10man & Mimiron 10man normal mode. Sadly i only can provide screenshots Auriaya Mimiron

Mimiron P1: Tank&Spank. After the fourth Plasma Blast he should be dead.
Mimiron P2: Summon a damagepet & move circles around him with fox. Otherwise the damage from Rapid Burst & Heat Wave would kill you. Dodge Laser Barrage & Rocket Strike's.
Mimiron P3: Standing at the entrance is a good idea. Summon a tankpet & attack Mimiron's Head with misdirection. Ignore Bombbots & send your pet with growl at Assault Bot & Junk Bot. If a second or third Assault Bot is spawning, use feign death. They'll go to there spawn position and wont do anything. If Mimiron's Head is at about 40%, kill the Assaut Bot & use Magnetic Core. Now finish him.
Mimiron P4: Dodge Rocket Strike & Laser Barrage. Easy Tank&Spank. Dont forget, all three parts from Mimiron must die within 15seconds.

Auriaya: Send Pet at Auriaya & kill her two Sanctum Sentries fast (they are doing much damage). If she casts Guardian Swarm on you, get near Auriaya and multi shot her. It will hit (and kill) the guardians. When the Feral Defender spawns, you have only three options to attack him. First is feign death, second is Disengage, third is when he jumps on your pet. When the Feral Defender is dead & Terrifying Screech is on cooldown use bandages. Interrupt Sentinel Blast with Silencing Shot & dont stay infront of her or you'll take 30.000Damage from Sonic Screech.

Kologarn down.
Durendil vs Kologarn - YouTube

I am so sorry for the loss of the first part of the video.
Anyway, this fight is all about Randomness. I used the same strat for 2 Hours until it paid off.
What I did was stand on the line that marks the entrance to Kologarn's room, use an aimed shot (no misdirection) and then send my pet. I had deactivated growl to stay first in aggro.
I have no real idea of why stone grip works some times and not other times. I believe that if he casts stone grip while he's targeting your pet, you are gripped, and if he is trying to hit you, you aren't. But I remember times when stone grip failed and my pet was first in aggro... weird.

I figured out how Jider managed C'thun.

I have no idea why, but the Stomach Acid gets dispelled when you run into the center of C'thun's hitbox. He'll knock you out, dispel it, and soon enough eat you up again.
As you might notice from Jider's video, the time you spend inside the stomach is very random. Most often you get teleported out instantly. Sometimes you stay for a few seconds, and if the tentacles inside spawn fast enough, this will give you the opportunity to kill them.

I haven't managed yet, but I'm 100% certain of the possibility.

Eredar Twins and Muru down in Sunwell.

Eredar Twins - Hunter Solo - YouTube
M'uru - Hunter solo - YouTube

When soloing bosses, if I can I'll pre-buff myself with my cat and wolf for str/agi, crit, and call of the wild. Reducing the fight time by a little bit if possible.

For the twins, as long as you stay out of blaze patches and feign death conflagration your health will be fine for most of the fight. I killed Alythess first to remove the flame buffet from the rest of the fight. After she's dead, Sacrolash will cast conflagration faster than your feign death comes off cooldown. Roar of Sacrifice those you can't feign to reduce the damage.

M'uru is even worse. You have to split your time between DPSing the adds and him. Otherwise your pet will be overwhelmed, or you never get DPS time on M'uru himself. I misdirect all of the humanoid adds to my pet in the back of the room, and only start DPSing them when a void sentinel is active. Kill the void sentinel to spawn little void spawns and AoE the pack of adds until most of them are dead. Your pet can finish off any others you have left. For the dark fiends, you can feign death to despawn them if you wait until they've start to follow you. Phase 2 is simply stay away from black holes and dark fiends.

With that all done, hunters can solo 5/6 in Sunwell now. Since you can just walk around Kalecgos, it's possible for hunters to solo farm for Thori'dal now!

Hunter Solo #Yogg-Saron : One Light in The Darkness# - YouTube

One Light in The Darkness Solo

And the last of the Archavon family is dead! (Toravon down.)

Toravon the Ice Watcher - Hunter Solo - YouTube

The only thing that can kill your pet is frostbite stacks building up. Since I couldn't distracting shot Toravon, what I did was either dismiss my pet or despawn my pet through outranging. Recall your pet immediately so frostbite can slowly tick off. While all this is happening you need to be moving constantly to keep away from Toravon, disengage + aspect of the cheetah works fine for this. Misdirect your pet at any moment when it's been recalled. When frostbite is about to fall off feign death so that he'll go back to your pet.

If you didn't misdirect or your pet didn't hit him, he'll just despawn so be careful.