Way of the Wicked GM here, about to run probably the last session of the last book with my group on Tuesday. I am very surprised to hear your friend refer to it as a kitchen sink setting. I think that is true of Golarion (the Pathfinder universe), but I would disagree that its true of Talingarde. The writer is quite specific that this is modeled after medieval England. That is why the player's guide discourages players from choosing gunslingers or eastern themed characters.

Here is some info dump about the setting. Hope it helps.

Races The populace is almost exclusively human, with smattering of elves and half-elf. Halflings and gnomes seems around but uncommon. Dwarves are a little more common, but there are several occasions were they have been shown to suffer prejudice. Not sure how your GM is planning on running things, but I would expect any non-core race, except perhaps Aasimar, could expect suspicious side-eyes from the general populace...so I wouldn't count on a Fetchling not receiving racism.

There are also two native groups on the island that don't entirely gel with traditional Talingarde. First is the Iraen (think Celts), who occupy a vast forestall region called the Caer Bryr. The Talireans think this to be part of Taligarde, but don't actively control it. There is definite tension here. The other is the Yutak (think Inuits) who have their own island to the northeast. They mostly have a live and let live relationship with Talingarde.

Religion Religion is a big player in the setting. Mitra is almost totally dominant on the island. Asmodeus is despised and hunted. The inquisitions were most aggressive with the previous king, but still do happen. Other religions are not necessarily illegal, but far from encouragde. This is implied to be one of the major causes of tension that Talingarde has with dwarves, the Iraen and the Yutak who all have their own non-Mitran gods.

Mitra themselves are not-so-subtly modeled after the medieval church. Structurally, they are similar to Catholic church, just with a high cardinal instead of a pope. Morally, you can expect them to be quite puritanical.

Magic Most Talireans have a fairly negative view of magic. Arcane magic is not illegal, but those who study it are looked upon with distrust. While there are colleges in Talingarde there are not colleges specifically focused on studying the arcane. Oddly, there is also a prejudice against divine magic, even within the Mitran church. This is largely attributed to jealousy. As such many high ranking officials in the church possess no magic whatsoever. Those Mitran priest that do cast magic tend to be more wanderers and adventurers than figures with political power.