"Always with you it can not be done"

The reflections are doable.

The film has forward footage from the biker's point of view, loop it, flip it and you have a reflection element.

Take the same footage and render it as a silhouette and you have a tree shadow element (after a bit of distortion).

It doesn't have to be very accurate as most of the footage doesn't need reflections and those that do are mercifully short (the bikers are also not wearing mirrored lenses so that can hide a lot of kludging).

It's not easy but it's not impossible.