You won't get the F seat. That flight will go full in J and F unless there are a lot of missed connections - there are a high number of HNW individuals and Golds and Plats too. I woulnd't hold your breath! I had to fly GVA DXB in Y this year too!

As for compensation, this is an unusual situation, they should have found a seat for you but it is a force majeure event ie outside of EK's control. I wouldn't rely on getting anything from them after you take the flight - they fight claims hard. Best to negotiate now - perhaps a free flight in original class of travel? That as JD said is only given when you are "offloaded".

Good luck!