These are notes from me playing around with an archipelago setting. As I'm having a clear out, feel free to use them if they take your fancy.
Topsy Turvey (hot in the north/cold in the south) so southern hemisphere (different for the sake of it?). I'm torn on this - part of me thinks a cod medieval/renaissance setting that just happens to be set in an archipelago would work just as well if not better than something a bit different (as in New World settlement analogies).
Southern hemisphere - strong New World focus. The events that led to the current set up are fresh in people's minds and there's a strong feeling of nostalgia for home.
Northern hemisphere - strong medieval focus with the events that led to the existence of the archipelago having a Wind Waker like feeling - they're the events of legend rather than fact.
For this version we flip over the setting to make it in line with a Europe analogue.
High Fantasy with elements of gunpowder, tribal magic and with a heavy emphasis on sailing/ships.
Exiles in a strange land in the Southern Hemisphere version - fleeing something (a demon/dragons? - This has shades of Ember the Thrice Cursed from Sharoban)
The land drowned (literally)?
A plague - giving a Land of Rice and Salt flavour to the proceedings?
Demons broke loose and overwhelmed the inhabitants.
Exile culture is drawn from Spanish, Portugese and Italian in the main.
Northern hemisphere would be a bit more European but I think the southern/Mediterranean cultures would be good to have as the powerbrokers with the Germanic/English ones as less powerful, smaller and weaker.
Kingdoms and realms cast from the remains of old nations, old grudges carried forward.
Racial tensions - cultural clash between nations, between exiles and natives.
Natives - humans or abhumans? My initial instinct is both, with some of the exiles being elves and dwarves etc, though if there's an elemental connection between the dwarves and the land they come from (which seems to make sense) then I think they'd have mostly perished on the way to the new land.
Dwarves are literally children of stone - they don't travel on water well.
From 'Europe' the Small Folk, comparable to the race from Memory Sorrow and Thorn, they take on the tendencies of the places/elements they live by.
Alternatively, go with utterly different races - Jaguar people, Macaw people etc. In this situation would it be best to jettison the idea of the faux Europeans having seen any other races before?
As I have the other archipelago setting I could try to incorporate some of that in this - perhaps if I go with a northern hemisphere setting, making alterations to the races to make them fit more or retrofittng the elemental themes to traditional fantasy races (the Dwarves as stone children already reflect that).
Dwarves - Stone
Elves - Wood
Djinn - Fire? - not Djinn - I'd like a sort of swashbuckling race (and wonder if a sort of Tsrang type people would work best).
Undines - Water? - I'm not sure how to integrate this idea which is always the problem with this elemental idea. Orks?
Rich Merchants - prosperous cities that have grown up from the landfall sites.
With a lot of the nobility perished in the flight from the homelands and the loss of their lands, the merchants have been able to become real powerbrokers.
Northern version - a plague has catapulted the merchants into the driving seat of power - they are old and rich families too because of the land drowning.
If there's been a transfer of power/conquest then it must have been gradual with many native people's initially welcoming the refugees and then finding that they slowly had their lands wersted from them. This creates the split between the areas of the archipelago where the old powers (Aztecs/Mayans and Incan empires basically) hold onto power and the newer places.
Powerful wizards - a guild of mages who do wind and water. They contract out onto ships and pay money back to the guild.
Their insignia is three waves
They can shape, summon storms/winds and use water for divination
They actually have a second 'house' - somewhere cold which focuses exclusively on ice magic (but if there are geysers there they might have a subset of steam magic)
Every year they have a water shaping contest
Shadow magic is forbidden but sneaks into the way things are taught anyway.
Dragons (in perhaps a more natural habitat than usual given this is the tropics). A reach in the archipelago that's dragon country. Large black volcanic sands for sunbathing etc. If topsy turvey - then this should be near the north, perhaps the last part of the old world?
Feathered serpents in the jungles? (Southern Hemisphere version obviously).
An underwater demon - bound in sleep. Ancient evil, a cult is trying to wake him. (maybe change to a volcano demon?)
An inevitable evil cult is trying to wake the sleeping terror.
Fire mystics in the north, in the hottest land. They swallow smoke and seek ecstatic visions (perhaps a 'native' practice). This is the only place where fire magic is practiced openly - it has a bad reputation. They stay the same if its a northern world just get flipped to the south.
Shamanic magic (perhaps but I'm wary of going 'natives have shamans')
Last vestiges of the Incan/Mayan like culture who ruled the archipelago before the exiles arrived, now limited to one part of the archipelago -
No horses, large birds instead? Or, horses are a sign of great wealth and out of the reach of most people (highly protected because they are all descended from the horses the exiles brought with them).
Landing Day - a celebration across the archipelago.
Burial mounds/cities of the dead, guarded by 'Draugr'.
Holy symbols keep them at bay, but they certainly cut down on graverobbing.
What about drowned burial mounds (northern hemisphere) - do the dead walk?
Red Water - a portent of dangers and evil magic.
Place - Andan the Shadow Port, pirate centre hidden in a small archipelago. It lurks in the shadow of a dragon's lair and the pirates use this for safety. For the dragon's part she finds it amusing to have a pet group of humans and is subtlely influencing them to create more mayhem.
Place - Amaya's Tears - a port city and a landfall site. There is a large 'garden of reflection' here and once a year the city holds a festival where pilgrims gather to remember the dead and their lost homelands.
Southern version - this is fresh and the cult of Amaya (Goddess of health and death) is powerful here.
Northern version - this is old news, few people do more than pay lip service but the cult is powerful enough to gather people to its bosom.
The city is heavily patrolled by the guards and the city takes every effort to sweep the streets clean of the poor and destitute.
Ruled by the Vincenzo family, a group of wealthy merchant princes.
Kingdom - Whitemarch (named after the stones there). France/England equivalent?
Place - Port Hammer - famous for shipbuilding. The front of the city is all ship building places and ports.
Place - Storm Haven - a large city with a bustling populace (focus for the setting, Waterdeep style).
Zephyr House - College of Magic
Dragon Plaza - history says that this where a dragon who attacked the city was slain. Its skull sits on a plinth in the middle of the square.
Green Acres - The rich part of the city, where the nobles and rich merchants have their mansions.
The Drop - a cliff that is often used by the local thugs, heavies and other criminal types as an assassination place (they literally drop their victim off the cliff).
Stone Mages have raised artificial islands in the bay to accommodate more people. These are often given over to more industrial pursuits.
Place - Caer Merddyn - Capital of Whitemarch, sits high on a hill in the middle of the island.
The White Palace sits at the top of the city
Tight spaces and crammed streets.
Place - The Higlands - Whitemarch's higher lands where the burial grounds sit.
Island - A forest isle where Elves live, they fiercely protect their home from intrusions but have had to give ground. (FATE tag - Cornucopia of medicines)
Place - The House of Amaya - a hospital and research centre for medicine.
The elves hate the intruders as their memories are bound up in the trees (the older the elves get the more they invest their memories in the forest so that they don't become overwhelmed).
Sea - Fire Reach - the centre of dragon activity
Sea - The Troll Sea - monster haunted
Sea - Heart Sea (central to the archipelago) - lots of trade, pirates
Sea - Shadow Reach (far west) said to be the way to the lands of the dead