At low speeds, the bottom leaves would produce aerodynamic instability (would tend to flip the craft) unless balanced by the top ones. That creates some scary failure modes. Meanwhile, if the top leaves worked as you wrote (unfolding at the tip), the air stream would tend to drive them toward full openness rather quickly. The forces involved could cause an issue (think of an umbrella inverting in the wind). Getting it to work as intended could be challenging.
At super sonic speeds, the way shock compression works, it’s unlikely the top leaves would even sense the airstream. The bottom leaves would create shock fronts which would drop the air velocity around and behind them to subsonic speeds, thus the top leaves wouldn’t help to slow the craft at high speeds (and probably wouldn’t help stabilize the vessel either). For an example of this, the grid fins on a Falcon 9 (despite being full of holes) will completely block airflow at super sonic speeds because the shock fronts overlap in the holes. Note also that the grid fins are located high on the vessel, to encourage stable flight while landing back end-first.
I guess, in short, the top leaves could make sense, but the bottom leaves are problematic. I wonder if you could run a mesh between them and get a kind of “flying squirrel” flaps for extra surface area and strength.