"The gravitational potential energy of the falling mass may be converted to other forms of energy"Does this mean it is possible to use the falling mass and trigger another release mechanism such as an elastic rubber band release mechanism.

It is possible to do that, but we are not prejudging a specific device. Per Rule 3.c.. the falling mass must transfer all of the energy needed to propel the vehicle into that elastic band. The elastic band must start with zero potential energy and must not have any stored elastic potential energy prior to the falling of the mass.