Thank you both
I found
a post on Warcraft Hunter's Union that briefly describes how to solo some MoP bosses. Horridon's really quite easy once you get the hang of it, just bring a Tenacity-specced tank pet and some decent gear (I started soloing him at ~ilvl640 and currently have 664 but it might be doable with lower gear and some good survivability skills).
I start by bursting him where he stands, then drag him over to the first door when it is about to open. I personally like to keep my pet on Assist to help with the trash but it might be easier to avoid the double-swipe if you put it on defensive/passive and Move To near the door. Misdirect and focus the small adds when they come out; they can easily be AoE'd along with Horridon. Same with Dinomancers - be ready to interrupt their heals to keep Horridon from getting too high, though if he gets close to 30% later on and you're worried about Jalak coming down don't be afraid to let the 'mancers heal him a bit. Remember to pick up the orbs the 'mancers drop!
The third door is where you want to be careful as the small adds that come through the door apply a nasty stacking 5 minute debuff that deals damage to you if they manage to melee hit you. They need to be kited and nuked fast as they tend to fixate on you, but if you're far enough away they should run for your pet instead. If you do get hit try not to let your stacks get too high or they'll kill you fast. Bring potions just in case.
Once all four doors are broken get ready to misdirect Jalak when he jumps down once Horridon reaches 30%. He hits hard and Horridon enrages when he dies, so also be ready to revive your pet, but he dies pretty quickly so burst him out of the way then finish Horridon.
If you need tips on Jin'rokh too it's pretty simple. Pet tanks, and avoid the Focused Lightning when it reaches you. Be sure to spam misdirection though - I always have aggro issues wherein he'll randomly come over and attack me instead, which is not good because if he grabs you the fight will reset. He can't grab and throw your pet. No water pools for extra damage will spawn though but he will still cast Lightning Storm. The damage is pretty low though especially if you use Spirit Bond.
As for glyphs and talents, I use Spirit Bond and Glyphs of Mending and Misdirection. You'll need the extra healing and misdirect spam. Exhilaration and Glyph of Liberation might work too if you need to quickly heal yourself and your pet.