That’s not a terrible idea, actually. The wheel (bridge?), in both my and Al’s opinion, is a crucial basic element for the bodyweight athlete. As for the L-sit, it’s often suggested that if you build up to a 30 second hold, it will set a strong foundation for front lever and planche training.
I would also recommend doing a good amount of Australian pull ups. Not only is this one of the most fundamental pulling exercises you can do, but it is a great low intensity exercise to help build stability in the shoulder pulling muscles and rotator cuff.