Does a person praying a fardh prayer receive the full reward of congregational prayer and enter among those who have attained the virtue of the opening takbir for forty days if another person prays with him with the intention of a supererogatory prayer?

A person attains the reward of congregational prayer if another person prays with them, because the minimum for a congregation is two: an Imam and a follower (ma'mum), and there is no disagreement on this. The fact that the follower is performing a supererogatory (nafl) prayer does not affect the Imam's attainment of the reward for congregational prayer, as the form of a congregation has been achieved. It is hoped that the reward for catching the first takbir will also be obtained in this situation.