Stranded with the above poster

Ask her to make a portal and get out from there with her.
Using whatever the island has to offer, discover how to brew their own booze in record time and party hard until either a) help arrives or b) they find something to make a method of transportation with.
Goes hunting, ignoring the gnome completely, if allowed to choose one of his pets to come along for trip he would pick Spike the devilsaur.

Cheat answer: pick his turtle and simply sit on it while it swims to the nearest and largest landmass, again ignore the gnome. "Hexie no lik' dem small ones, talk tu much n make 'ead 'urt."
Let him do all the hard work, like hunting.
Relax with and talk with doing the lovely nights, when enough time have passed, prepare to find a way to either settle for a long while or build a raft/boat

Cheatsy answer: Rift/portal to the nether
Kill her quickly! Shes clearly demonically tainted so Kelastra would kill her without question. (or die in the attempt). Either way one of them dies right away and the other tries to make it alone. Kelastra has alot of hunting experience and with a fresh warlock corpse to use for bait....she would use it to try and hunt. If not she would fall back on her fishing skills!
Attempt to convince her not to kill him right away, then co-operate in surviving on the island. Out of the two, Kal'dorin would likely be the biggest whimp.
Sadly, since Rogues simply cannot be trusted, Ailred would be compelled to cut down the Blood Elf. A member of the other faction whose motives are unknown and who is very likely to kill him in his sleep? It would be rather foolish to take any chances in that regard.

Sad, because he would have been more co-operative with someone whose motives were more agreeable, and who could be more trustworthy.
Again, with the assumption that something is stopping Sa-Matra from simply popping a portal to somewhere neutral, have the human and herself make their exit through it, shake hands and part ways...

So long as factions aren't brought up, Sa-Matra wouldn't have issues getting along with Ailred. Nonsense aside, they're stuck on an island and killing each other because of something stupid like factions would be highly counter-productive. In her opinion, anyway.

Beyond that, I can see it working out, with a fair share of the workload and planning things out together, eventually making it out of the island. Or surviving until help arrives.
Either two things will happen.

They'll work together very well with sorting out how to get back home, and will work together to survive long enough for it.

Or they'll not want to leave.

Or a middle ground, in which they're found in a highly compromising position ala James Bond when rescue does arrive.

Or just the first one.
Probally either -try- to work together with as little communication as possible and as little interaction, or outright murder him, a good source of food and his armor could be used to adorn her felhound, maybe even her succubus
Offer a portal out of the island.

Mages ;)
Make the easy get away more exiting by doing portals to eachother.
Since Corny's powers don't seem to be effected by this mysterious LOST styled island ...

... Goldy would simply hold his hat hostage until he agrees to portal her to safety.
Build a marvelous "mechanic" boat using wood, stone and what else may be around, then plant a lovely chair, incline Lady Goldishia to take a seat on it, as he slowly sail them home.
no i will just kill him. since im a dk i don't need to eat or drink or sleep so surviving will be easy because the only thing i have to worry about is getting killed by something
Assume Fizzlon was somehow responsible for their shared predicament, and threaten him under pain of death to revert whatever mistake he clearly made.

If both gentlemen would make it out of that initial round of playing the blaming game, Valdreth would gradually thaw towards his only social outlet available.

-- Edit --

Kind of the same with a worgen DK, although he'd probably avoid interacting with him whenever possible. That or simply burn him, hoping that the smoke might signal someone.
Broch would size him up, and try to determine his strength. If he looked at all vulnerable Broch would do all in his power to end him swiftly, to remove a threat of deceit, or need for sharing resources. If Valdreth was in a position where he looked strong though, Brochov would try to be peaceful. Make the argument the elves and humans were allies once, and can be again on this little island.
Do her best to convince him to co-operate, and as they survive on the island together, slowly corrupt his mind and soul 'til he's little more than a slave, then leave for Booty Bay on a raft, taking him with her as her personal assistant for all eternity.
Plant the banner of the Forsaken, claiming the island for the Dark Lady and then setting up a very small Forsaken outpost.