Is it necessary for all limbs to be still without any movement—even a finger—during the period of tranquility between the two prostrations and after rising from bowing?

"Tranquility (ṭumaʾnīnah) is obligatory in all the actual pillars of prayer. It means the stillness and stability of the limbs for a period of time, the minimum of which is the attainment of stillness, however brief. The worshiper must remain in the bowing position until his limbs become stable. Tranquility is also obligatory in the sitting between the two prostrations, and this is the view of the majority of scholars, who cite the saying of the Prophet, peace and blessings be upon him: 'Then raise yourself until you are calmly sitting.' Similarly, tranquility is obligatory after rising from bowing. Its minimum is for the worshiper to return to the upright posture that is sufficient before bowing. The complete form of it is to stand straight until every limb returns to its place. Slight movement, such as moving a finger, does not affect tranquility, but it is not legislated."