Stranded with the above poster

Grimrose would simply sigh, letting the Tauren leave. He'd eventually just get on with life; if there are rocks, or trees nearby, fishing spears are a go. Otherwise plantlife and whatnot are viable - or possibly even perching migrating birds to eat. He'd be fairly content to wait his time out until found, rescued, or until a raft had to be made.
I'm fairly certain Duskwraith would get along with Grimrose fairly well, should they ever end up stranded together. He'd most likely keep his distance and not seek much in terms of conversation, but would be likely to give a helping hand in ensuring the Worgens survival. Other than that, he'd spend his time in meditation and tormenting whatever wildlife might be around to keep himself sane.
Cathríon would be extremely wary and work along side the Death Knight as little as she had to, hoping to come up with some means of escape before he did something to offend her greatly. Her obvious disdain for the Undead regardless of race, faction or allegiance would be rather apparent, though Daeran may confuse this for a general misanthropic vibe. The moment she catches him torturing any innocent wildlife would be an interesting confrontation which would probably result in her realising she will have to plot to murder him ...

... along with the regular vials of poison she carries, there's always one filled with the most potent "poison" one can use on the Undead ... holy water. So, there would most likely be bad times ahead with only one surviving at best, that is of course, provided they couldn't escape the place within the first few hours.
Yani would be a little wary, since she's very much a lone wolf. Also, she tries to play things as close to Neutral as she can get and has learned the hard way that the rest of the Horde don't all share her point of view. Depending on how fervent Cathríon is about fighting the Alliance, Yani would either offer a cautious greeting and work with Cathríon to try and escape the island, or stay well on the other side of it.

However, it's worth noting that if Cathríon has any battle pets on the island with her, especially of a kind Yani hasn't seen before, then Yani's curiosity and love of animals would get the better of her. At that point, even if Cathríon is making a banner which reads SLAUGHTER THE ALLIANCE out of banana leaves and seashells, Yani would at least attempt to strike up enough of a conversation with her fellow blood elf to learn where Cathríon found those pets.
Giggle and lie to relax abit while she did all the work
Given Rumikah's overly murderous nature in regards to eating people, draining souls, and otherwise acting in an extremely hostile and debauched manner, Ailred would be compelled to kill her. There's no way that she can be trusted to co-operate.

After this, he would go through all the hoops necessary to allow himself to escape the island.
Try be as helpful as possible to Ailred. While being very curious, ask alot of questions, examining things everywhere, all with very impulsive enthusiasm.
So most likely being more annoying and in the way with some rare moments of helpfulness, than actually being helpful.
First and foremost figure out whether she likes Nadine. If so, offer a free portal off this bamboo-forsaken island. If not... charge money for it.
Rauma would help Sunami in any way she could; however, since she would remain permanently in Druid Cat form while doing it, her help might be a little limited. She'd be happy to fetch and carry though. Also, she's been acting more feral lately, so she might disappear for a while to hunt.
Nathrael would most likely sit down, stare out over the ocean, and gently pat Rauma if she'd allow it....
He'd not say anything besides sighing once in a while and say, once, "I wish people would summon warlocks for once..."

Besides that, he would not be much company whatsoever, pondering about life and how to get away from said island without speaking a word out loud about it.
Given Isaryon's rather extensive training for surviving out in the wilds, he might not be in much of a pickle. Given that the human is an enemy, the Ranger would very much avoid him. Were there no truce, of course, it would be a different matter. For the most part, though, Nathrael wouldn't even know Isaryon was there, given his musings while the Blood Elf is avoiding him.

With his enchanted waterflask, Isaryon isn't in much danger of dying from dehydration, and with his Ranger training, he can either fish or hunt as needed - useful tools that he would have happily allowed more friendly companions to share in. By and large, he would simply survive and surreptitiously build a raft or something with which to then escape... or just survive until help arrives.
"Refrain from making a cow joke and i'll help you waterwalk back to Kalimdor. Moo so much as once and you will be left to swim any which way you'd like to."
30/03/2015 01:44Posted by Túwa
Refrain from making a cow joke

Kaaya would be A-OK with that request.

Hence it'd probably be a pretty short and anticlimactic experience.
Ask her to tell some Tauren legends and stories for her collection.
Plan, cooperate and work. Both Terintha and draenei and been through a lot worse than being stranded. Despite the loss of gifts and abilities, seeing through enough trials and tribulations has shown that when there is a will, there is indeed a way. And there is enough willpower between a draenei and night elf.
To Idaris, being stranded on an unknown island is just another opportunity to do what she loves: explore.

She's already used to living off the land, and if Terintha can put up with her lack of personal hygiene the Draenei alone can ensure survival, so long as there's means to make shelter and something to feed from on the island.

It probably wouldn't take long for Idaris to know every nook and cranny in the island, and the two could make a decent living until they either find a way out or help arrives.
They would get along well, as long as she doesn't tries to zap Hex or anything.
But he would be vary, as he knows not all alliance members can be trusted.
He would probably try and make a connection with the animals who live on the island, have them aid them in surviving.
While she would know the whole island 'design' wise, Hex would figure out the best hunting places and where to get fruit from.

They would probably survive without anything eventful happening, maybe if the saving takes too long and one of them figure "I could kill him/her and no one would know."

side note:
Hex doesn't have the best hygiene either, so on that front there wouldn't be a problem, he might welcome someone who smells as bad as he does.
She'd find no problem cooperating with both Hex and his draenei ally. She has spent the last few decades living alone in the wilderness with only beasts to talk to, so, it'd be like a holiday for her. Heck, three hunters? They'd build themselves a nice, cosy hut or find a nice cave and make it homey. A few skulls and pelts on the walls, a nice fire, the hydra dozing in a corner.......

She'd insist on regular baths however. Even if it means tossing someone into the ocean with a soap on a rope strung around their necks! You can easily make soap using animal fats and scented flowers after all.
See, being a hunter is great. Both Trakmar and Firetrap could pull their own weight, hunt, fish and generally make sure they don't run low on food. He wouldn't have much problem with her presence as long as she wouldn't provoke.

And considering Trakmar is a cannibal, it's good to have some back-up food, in case we'd make the island void of anything to eat!
Well. In the interests of survival, Isaryon will likely share his waterskin with Trakmar to ensure that neither of them is at risk of dehydration. Of course, given its value, he'll be sure to do everything in his power to ensure the orc doesn't just steal it. Enchanted water flasks/skins/whathaveyous really aren't cheap, after-all!

As for the rest, well, that would be a case of careful rationing and co-operating to ensure both can survive long enough for either help to arrive, or for them to escape. For his part, at least, Isaryon would keep his appetite in check to only eat the necessary amount and variety. Whether or not the Orc can will likely be the decider between how co-operative the Ranger will be.