As the ship sails away from the infernal island, there are two they can reach and still make it back to the group they left on the other island before nightfall, one to the east, one to the west. It will have to be a short exploration as well, else they will likely arrive after sunset.
Ilia's in favour of exploring again, but can be talked down to just sailing around the other two islands looking for anything interesting by her slightly singed colleagues.
I vote that we use the sand picked up to make a permanent arcane connection to the demon, research a big Perdo Vim spell, and blow it to kingdom come.
Aurore and argyros agree on the east one (or west)
Pierus also has no strong feelings on which island to check next; but he does suggest making sure they are back before nightfall - he'd like Brother Galenos to see the formerly-possessed sailor, to check for any lingering traces of the Infernal.
FWIW, the reason North was checked first is the idea that no matter where they are in the agean, if they keep heading North they are likely to find land, and probably the Theban tribunal. Land is more assured (eventually) in the east than the west, but there is the chance of it being Muslim lands or at lest actively involved in the crusades.
Euphemia suggests that it would be best to head back to the others post-haste. There are wounds that require treating, and Brother Galenos should inspect the ship and crew for signs of Infernal taint.
The slight majority concensus seems to be for the Eastern Island. Who would be going ashore this time?
Since I have to redo my Companion, Euphemia will go again. For she is brave! And pretty! Really, she's just so multi-talented. 
Pierus is keen, not having had a chance to examine that last one.
The captain would like to go ashore to make a few measurements so we know where we are. She'd probably stay close to the ship and wouldn't go exploring. She'd take one or more grogs with her. She's better at Artes Liberales than the magi.
I (ooc) am glad of this. I was hoping someone would try. Although my history is too rusty to know whether western astronomy in the 13th century was up to navigation.
Heading East you find that on one side of the island are cliffs, and spot what appear to be dwellings atop them, as well as what would appear to those with the keenest eyesight to be winches.
Angie will walk with them, despite being injured. Everything to get off the boat.
Argyros will go on this island.
I would very much like for Euphemia to meet and befriend a really cool familiar, such as an alicorn, dragon, or something nifty like that. Something that really stands out.
I don't really know how I would go about making that happen, though. I mean obviously, "Go look for one," but how does one propose such a venture? What Abilities and so forth are required?
Best start by building up area lore and perhaps a network of agents to relay information to you...
Or ask the faeries! How convenient that there are magical gossips about to inquire with...
So, I take from your response that there won't be any serendipitous circumstances which arise that are conducive to my goal of having a totally awesome familiar?
I'm not saying they won't occur, but they won't border on the miraculous.
All adventures are currently closed as the ship returns to the faerie island beach. From here do you want to travel to the mercenary island and try and make it before nightfall or wait until morning? What plans will you make for the next day? And remember- you have enough food to last through lunch tomorrow- if you have not found more food by dinner there will be none.
Euphemia suggests that the group should sail away from monster island, while they tell each other about what they encountered during the day. Once night falls and they're at sea, they can pull in the sails and oars, have a funeral for the lost, and sleep on the boats, then continue on to the island with the other shipwreck the next day.
That should expose us to the least danger and give us time to treat wounds.
Speaking of treating wounds, how do the men of the crew react to having a beautiful sorceress cast healing spells on them?