Stranded with the above poster

Slit his throat and create an icy path across the ocean with his body.
Tell him to build in a raft, as he doesn't want to get wet, then lie on the beach and let him do all the work while he "works on his tan". If he got bored, he'd probably just go and kill animals and random stranded people for his own amusement.
goes about making a suitable living place for himself, hoping Veg would help him, and if not then Vard would work on his own, occasionally ask Veg for help if he isn't offering it to begin with.
"You build the shelter and cook, I hunt for food and forage."
With that, Kosh sets off.
Disclaimer: Again, I'm going with the assumption that there's some force at work preventing Sa-Matra from using magic because 1) It's more interesting that way and 2) if she could use magic she'd just teleport herself and Kosh'amon to Orgrimmar, shake hands and part ways.

"That... sounds agreeable."
Although Kosh'amon is undoubtedly able to take care of both herself and Sa-Matra, she'd probably find the elf somewhat of a liability soon enough, as she is hinderingly wimpy without her magic. If the environment of the island is rich, the mage could be useful due to her vast array of knowledge - she probably recognises more useful plants and such than the orcess does.

Most of the time Sa-Matra could really only work as an advisor or sorts - mostly for matters Kosh'amon is unlikely to need any help which, so she might find the know-it-all elf annoying a lot of the time, if not even frustrating.

Still, if she has the patience to deal with the Magistrix, I can see them surviving fairly decently until help arrives or they find a way to get home.
Goblo would try a Death Gate but fail, noting the magic barrier preventing portals of all sorts. He would now head into the forest and start chopping down a tree. Once he's done that, he'd see the Elf sneaking up on him. "I can see you, y'know." He would remember a power he had and walk to the water. "Ready to head home, Elf?" He'd create an ice path for them, hoping to find shelter. If they didn't reach it by sundown, he'd get the mage to create some food. They'd eventually reach land and part ways.
Saturate him in Holy Light then fend for herself on the island, content in the knowledge that the Light will guide her, and through her faith, she will be saved.
Be grateful she wasn't stranded some some slack-jawed trogg and work in tandem with Ihriell to gather supplies, forge shelter and eventually find their way off the island. There'd be the occasional contention between Paladin and Farstrider, but nothing serious enough a little bit of sunbathing R&R couldn't fix.
Be glad that he's with the Horde and start work on a way off the island
Listen to Gobloknight tell her he's not going to wait on her hand and foot then let out a high pitched tantrum of a scream that lasts for ever.. and ever.. and ever... it seems she needs air less than he does.
Being very awkward and apologizing to Cogwizzle again and again that she cannot teleport them away since she hasn't learned that spell yet.
Then not helping at all with the survival except for trying to figure out how to conjure food. But obviously not being very successful.
Kill this incompetent fool and skate across with the elf on his shoulder.
Kill as soon as possible since he seems to be the murder randomly kind of death knight. Most likely by leting alot of roots crush and grow through him. Then explore and examine the island before flying away.
"Whad I tell ya, mon? Dat voodoo was all ovah ya pants, but ya din' listen ta Zet'jia, did ya?!"

Upon making contact with Erensar on the island, Zet'jia would assist him in whatever way required while he probably attempts things such as communing with the land to figure out where they are, and how they ended up in such a place.

Presuming for whatever reason Erensar cannot simply shape shift and fly them away (because that'd be cheating) after a few hours of research and the fact they don't actually seem to be in any immediate danger, Zet'jia would just start ripping the piss, trying to convince Erensar she's sensing some "bad mojo" from his clothing, become intent on having fun and taking it easy, attempt to scavenge plants for recreational use, etc. Basically she'd just end up completely relaxed about the whole situation while being quite grateful she's been stranded along side a fellow Druid. She'd help when asked, but probably wouldn't be bothered otherwise.

When he's not coming up with a way home, she'd pester him with a lot of noobish Druid questions. "How ya get ya feet like hooves, mon? Dat be 'ard, I ain't able ta shape shift ..."
Goblo would leave the troll on the island when he escapes
The gobln, as Razen would find out , is a selfish coward raised by the Lich King. Razen would slowly and surely set up camp as far away from Goblo as possible whilst thriving off it's resources.
Probably a mostly cooperative affair, where Ihriell would naturally take charge and delegate some tasks to Razen.
Well this could certainly go to a lot of directions.

The most likely one, I think, is that Ihriell and Kaaya acknowledge (even if perhaps begrudgingly so from Ihriell's end) that they're sort of in this mess, however they ended up in it, together and that co-operation will make it far easier for both of them. And since the pairing is a Sunwalker and a Blood Knight, I assume it wouldn't begin with or even lead up to open hostilities.

Having established that, Kaaya would probably gladly let Ihriell take charge and volunteer to go out to gather food for starters, and help setting up some manner of shelter before they start to figure out a plan to leave the island.
Stuck on a Island with a good looking female Tauren?

Ragorn might not leave the Island ever.
Well, Ragorn seems like a rather reasonable Tuaren. Therefore, in the spirit of co-operation in a mutual goal, Ailred would suspend any form of violence towards the Tauren so that they might work together to leave the island. So. Overall. They would work together to leave the island, and then go their separate ways with some newfound mutual respect for one another.

Hopefully.