- They have the potential to glide from higher trees onto passing animals
I think you mean parachuting here (close to vertical, drag maximized, no lift), not gliding (almost horizontal, drag minimized, lift generated).
Given their narrow wings, I don't think microraptorians could have been good at parachuting.
- The stiff tail could be a crucial adaptation: Allowing the animal to rotate once jumping (assuming an upward facing posture) off of its host and glide out of range of footfalls
Here you do mean gliding.