Okay so after attempting many different things to get this to unlock I have finally sussed this one out.
To add to iFilipK solution about waiting each week for a new season, there is a quicker way to unlock this all in the one season.
If you have Daily or Weekly challenges to do you can use the Event Lab to your advantage.
Simple load up an Event Lab race in the season you need, and complete the daily or weekly challenge in that event. Rinse and repeat for 4 challenges in each of the seasons and you're done
For example, I needed to complete a festival playlist event during the storm season and I had a daily challenge to Win a Drag race in a Modern Sports Car. So I searched for a Drag Race that had the Storm season on it and made sure I won the race in a Modern Sports Car.
I checked my progress on the tracker and sure enough it's gone up to 75%! Now I'll wait until tomorrow and do my next daily challenge in the season I need!
Let me know if you have any issues with this and I'll explain it more if needed, Happy Hunting!