Personally, I do not like the idea of five families. It looks too much like Prifddinas. It's not a good idea to be reusing Runescape 3 content, that's boring. I'm also worried that if you side with one family. You removed the content from four families. I prefer the first Port Roberts concept. Port Roberts could be the main tie between Asgarnia/Kandarin/Misthalin and the new continent, and resemble those areas more than the rest of the continent.
I'm not a fan of the fact that there are gnomes here which is a bit odd since they're not sailors. However, I do like the premise. The official authority that regulates trade between the new continents of the globe is the customs authority. They impose a heavy tax and can be very inconvenient. Some people are now using illegal smugglers as trade partners because they are enraged by customs officials. The battle between these two forces could be explored in quests and you can choose to side with any of them. Colonial Boston is the closest thing to real life.
All areas of Runescape currently comprise a portion of medieval Europe or the region to the east. For example, Fremmeniks-Scandanavia, Karamja-Sub-Saharan Africa, Asgarnia/Misthalin/Kandarin-England, Morytania-Eastern Europe, Al Kharid-Arabia.
That really only leaves Mediterranean/Southern Europe, so it would be logical for the new continent to resemble Italy/Spain/Greece. You could also include iron-age ideas. For instance it is possible to have two cities that are similar to Carthage and Rome (Carthage utilizes elephants, please).
Although they aren't at war The two sides are in an ever-growing conflict. The road connecting the two cities is heavily secured. If you venture there, you may encounter tough adversaries. There are two options to choose from: You can pick one of the cities "good" or "bad" and your character could choose to fight for either or both be equal. If you want to know more about can go https://www.rsgoldfast.com/