Stranded with the above poster

When Xirque find Cath ok the Island, he would cautiously try to get on her good side, like supporting her igniting the bonfire (he still is a firemage/destro lock, in the bottom for his demo training), BBQing the prey on spot, and supporting with guarding ( well st least command a demon to guardb them), but if she became fiendish, he would step back and try to rely on himself even though that he know that it would be easier to get help by cooperation. At least he knows that he will have support from the demons that he command, while Cath would be alone trying to survive.
At first it might seem like they get along fine, they do okay and manage to make the island live-able.¨
Until rescue comes, in which case Vard kills Xirque, telling him before he bleeds out.
"Didn't you wonder how we both ended up here in the middle of nowhere together? As your boat sank."
Then explain to the rescuers, that he acted in self defense.
Have a vacation!

After exploring the island and other boring necessary stuff I imagine it to be alot of lazy relaxing on the beach and censored stuff with no hurry to escape and just wait for a rescue.
You know, that plan sounds so good, I won't even try to change a thing. Count me in as your stranded buddy.
With a person like Alin, Ternezia would initially feel she's already rescued. There would be a strong sense of security and comradeship between the two.
Ternezia would feel that both do not belong to the island and would want to go back home as fast as possible. Alin might have a different opinion, so arguments may start. Especially if Alin fails to maintain a leading role and just wants to enjoy the moment, relaxing on the beach.

The more time passes, the more nervous she becomes, being without civilization and propaganda (which she expects to hear from Alin). Censored stuff is out of question if she is ideologically disappointed.

In the end both are eventually rescued, which makes her very happy.
When Daha sees Tenezia, he yells one thing: VICTORY OR DEATH.

The fight starts without any chance for Ternezia to argue with him.

After a while Daha has executed Ternezia, but.... Daha wasn't happy.... he is still stuck on the island. Not long after an Alliance fleet arrives, to rescue Tenezia, but they found only her corpse and Daha, trying to catch fish with her corpse....

Daha fought but died of the overwhelming Alliance soldiers.
VICTORY OR D-*BLAM!*

"As ya wish, kid."

After which Gibbles proceeds to make do on the island on her own until rescue arrives or she manages to build something to get off the island with.
Unfortunately it appears the Gnome woman isn't getting the time to do such. Starshards, some probably about the size of the Gnome, rain down upon her.

"Finally a quiet place where the Alliance won't act so suspicious for killing a supposed "ally". Her blatant use of Fel had to stop at some point..."

Kyrina afterwards is likely to survive pretty well on her own untill a way to escape the island shows itself. Being vegetarian is likely to be in her favor assuming there is sufficient plantlife on the isle.
With Kyrina most likely being hostile very fast to not only a blood elf, but also to one who doesn't hide what kinds of magic she dabbles with either, only one will leave the isle. Waiting until attacked Nimirah would either reflect Kyrina's starshards or moonfire back at her or silence her then kill her as fast as possible without any unnecessary torment.

She then tries to either teleport from it if not possible she will build a shelter etc and wait for rescue while calculating how likely that is. If it's estimated low she'd summon a dreadsteed and try ride across the water as a last resort.
So, it mhight be a lhong walk bhut, ya wanna walk to da mainland if I use mah path of frost? If yah get thired I'll just carreh yah, I can go on ahnd on.
Well, because the deadite really doesn't need looking after, Isaryon only has himself to worry about. If Dorethien is suitably friendly, he'll allow him to stick around and help out, though the Ranger would insist on being the only one to handle the foodstuffs that he will personally be eating. If Dorethien proves unco-operative or hostile, Isaryon will simply disappear into the wild on the forest and live off the land until he can leave with rescue.

Should the troll offer him the opportunity to get away with the Path of Frost, Isaryon will flatly decline, as he doesn't know whether or not this troll will just simply dump him in the middle of the ocean, where he would be well and truly screwed.
Once Calork have assured Isaryon that he isn't a member of The Iron Horde they can begin to cooperate.
Isaryon gets the food, Calork does the 'basecamp' building.
They'll manage, either till a rescue team comes, or they get a raft built.
As a hobby fisher and a master in making fire (both with the traditional way and Arcane/Nether energy, Xirque and Calork would probably stay alive as long as Calork would be able to trust the Halfdemon Warlock, Xirque would on the otherhand have deep understanding if Calork are mistrusting and may then eventually tru to cross the water on a felsteed.
It would begin well, Astrophel isn't keen on the use of fel magic, but considering their situation, he'll let it slide as he discovers he can't simply teleport himself out of there.

Astrophel's tolerance would reach breaking point when Xirque uses his fel energies to sear bugs for amusement, boiling surplus amounts of fish in a pond for food and toying with an imp's mind and freedom when idle.

In the night, the mage would brave the sea with an enchanted make-shift raft. Tackling the treacherous waves were preferred to enduring space sharing with the fel elf.
Hex probably leave Astrophel alone preferring to deal with the island by himself being quite used to that.
Should Astrophel try and help Hex, Hex would just tell him to go away.
2 troll hunters on an island. I think we'll do just fine. Still... Cerebrate wouldn't know what tribe the other troll is from, so he will aproach carefull, hoping for the best but having his gun ready.
Once Cerebrate trust Darj, he uses the trust to murder Cerebrate and use his body for survival, preferring his odd alone even if it means he'll die, but the biggest use he'll have for Cerebrate is to sacrifice his remains to the Loa that most likely reside on the island.
Abbendix could teleport, using her affiliation to the neither she got while associating with a Tothrezim... maybe she will help Darjin get out of the island too, if he wasn't too agressive.
Briefly tolerate the Blood Elf's presence ... that is, until she begins to reveal her demonic history and suggest things like skipping through the Nether. At the point this becomes known, Elandris would eliminate her when the first opportunity to do so effectively presents itself.

She is more than capable of surviving by herself.
I imagine this would largely depend on whether or not Elandris will feel inclined to try murdering Rodeldë from the word "go".

If so, they have their fight to the death and whoever lives will either die to their injuries or carry on with the survival shtick by themselves - with varying degrees of success depending on which one survived and how unscathed they are.

If not, they'll begrudgingly form an alliance of convenience until they get back to their respective territories where, I imagine, they'll both put a lot of visible effort in not jumping at each others' throats immediately as they go their separate ways.

Of course, if they do co-operate there's always somewhat of a chance they'll jump at each others' throats over whatever petty reason before they get away from the Island™.