Well I apparently missed an npc somewhere, because after talking to everyone for a fourth time... I managed to get an npc on the slime field to the left exit of the city and there was a cook there, then I talked to everyone again just to make sure... and I was able to exit through south of the city.
I've beaten the boss there and now I'm stuck again, no damn clue of what to do now.
I have obviously talked to everyone again lol...
Edit* Ok... I think this is going to be one of those games where you don't have a damn clue whether it's bugged or it's story progress... I just talked to everyone again, clicked everything and I couldn't go through the east exit of the city, so I decided to check out the plant area again (south exit) and the boss was there again, I was like: dafuk?
So I beat him again and talked to everyone again and I was able to leave through the east exit of the city lol...