I do understand the financial situation of Everton and I also know that he is unproven at that level.
But he is one off the best midfielders in the Belgium League. (after Biglia which is a great defensive midfielder)
RSC Anderlecht ask 11,000,000€ for Biglia. I think 7,500,000€ would be a good price for Vadis.
But after all, if Everton could buy him for 5 or 6 million euro, I wish Vadis and Everton good luck. (I know he will be a good player for your team)
If he feels good, you can expect this: