In honor of those who ascend to unimaginable heights. May your spirit continue through the dreams of others who follow...
The interesting thing is the disappearance of not just Alaina, but the two children as well. I thought at first that the family moved out of the house, seeing as Alaina took her husband's death at the Broken Shore badly and there would only be painful reminders in the home. You pointed out to me, however, that using "/target Alaina" will target Alaina Hearthsong... dead.
It's possible that she committed suicide, but there is no visible body or other indications of what may have taken place. I personally believe that, as despondent as she was, she only moved out with her children. Blizzard does make use of 'bunnies' to trigger spells or otherwise provide a mark for the game client to use as an indication to do/show something. After returning the charred locket, the player does not see her or the children anymore. How does the game know to do this? With the hidden, 'dead' NPC.
Ok, nope. Looks like it is an environment bug. Some players are able to correct it by relogging (did not work for me) but I used Whole-Body Shrinka' to drastically change my camera's height. I was then able to see her corpse by clipping partly through the bed.
I haven't heard of this quest. I asked a friend who writes a lot of quest articles for Wowpedia, and she can't place it at all. I also checked the mobs linked on this page and there is no data for any of those creatures. It is probably safe to say that this never made it to live from Legion's alpha/beta phase. I will go ahead with marking it and the other quests you mentioned - no collected data for them, too - as not available.
There are three new toys for 2017's Lunar Festival. It requires three players to "assemble" the whole costume, which makes it/them unique (in comparison to other toys).
It comes to 60 coins total if you want to collect all of them. See my older comment on this page for locations of elders, or visit Icy Vein's Lunar Festival 2017 Guide for that plus other details.
What you are looking for are floating green balls called Volatile Fel. They are found in/near pools of fel... stuff. You don't actually have to be too close to one, since it seems there's a generous range on the spell cast by the quest item.
I solo'd this quest as an avg ilvl 832 Fire mage. Talents not optimal, but it helped me get the job done. http://www.wowdb.com/talent-calculator#Egoi What my artifact rank apportionment looks like: http://www.wowdb.com/artifact-calculator#iZbLbDJIBIAhifhkBAAA
Quaff a flask, it doesn't need to be an expensive one. (I still use Oralius' Whispering Crystal from WoD.) Eat a buff food, too. I preferred Fishbrul Special because it's an attack that doesn't cost me cast time.
Do not bother with Snaggle Sixtrigger yet. Your first target is Rax Sixtrigger in the mechanical shredder. Keep your barrier up as much as possible, use Blink on cool-down for sustained healing. Snare with instant-cast Flamestrike and Frost Nova. Do not stand in the bad that Snaggle launches at you.
When the shredder goes Haywire, you have two options: Ice Block and wait it out, or do what the game tells you and launch yourself up to the ship which Snaggle is attacking you from. Honestly, the Ice Block is the better option because of how much time the game takes to actually move your character from its position to where the grapplehook on the ship is situated; I took a lot of damage and this almost killed me in my first attempt. Unfortunately, IB has a long cool-down, so if you are high on health then get on the ship. If you are low, just IB and wait it out. Be prepared to Blink away, use both charges of Inferno Blast to get a quick Flamestrike on Rax, and heal up while doing some casting. Rinse and repeat, and Rax dies.
Now Snaggle's turn. Do not bother with getting on the ship. Dodging the timed bombs is simple and you never have to worry about dealing with Snaggle's special ability that forces you off the ship.
TL;DR - Do not stand in bad. Keep yourself healed. Focus Rax, then Snaggle. GG.
According to Blizzard, this is not on a per-realm basis - it is per region. This makes sense (to me) because some realms have huge disparity in faction balance.
I believe this will be a fun mini-holiday because it is rather friendly to players with alts. Even lower levels may participate by turning in specific items, like food crafting reagents, to an NPC (which is purposely reminiscent of the original Ahn'Qiraj quests that allowed non-60 characters to contribute to "the war effort").