Well 24 hours are over...and we only had one contestant who gave the right answer!
It's Racer1309! Congrats you won a Steam Code for "The Void"

The right answer was:
Isla Más Afuera renamed later to Alejandro Selkirk Island.
(both answers would have been correct)
The shown Island was: Isla Robinsón Crusoe but as I already said in the Hint, we didn't search the shown Island. It was just another hint to the real goal!
Alejandro Selkirk stranded on Isla Robinsón Crusoe...Daniel Dafoe was inspired by this story to write this book (Original title):
Click
with more than 300 letters. But since Isla Robinsón Crusoe isn't a vacant Island we had to look a little further to a small island not far away.
Alejandro Selkirk inspired anonther man to write this book:
Click
It also has more than 300 letters and one false information (The year of death)
If you want to know where this hell of riddle come from...every year from 1 to 24 december each day a riddle like this appears and you have 24 hours to find the solution. You can win prizes for every day and you can eget even bigger prizes if you are able to crack them all... In 5 Years I was able to achieve 2 gold medals for resolving all riddles one silver medal for solving 23 riddles, and 2 years where I didn't achieve anything lol...
Why do I tell you this? Because to let you know that the winner here has deserved my respect for cracking this headnut!
I also want to thank all the other attendees, for even trying to get this worked out! Thank you very much and see you tomorrow for the Final giveaway! (I'm out of codes then, but will try to get some more! hehe)