Have the values displayed each dt. These three cases will not happen at the same time due to precision errors. A range of values are acceptable. The slope of the Velocity vs Time line is acceleration. When terminal velocity is attained, the velocity no longer changes.
Terminal velocity is dependent on the object.
If the object is unchanged, then the terminal velocity is unchanged. The same terminal velocity value would be obtained at the same time for the same object no matter how much longer it is allowed to fall. Describe the distance graph. The distance graph is parabolic as long as velocity is increasing. Once terminal velocity is reached, velocity no longer changes.