While gathered for majlis at someone's home can we offer the regular prayers in congregation without a religious scholar to lead? If so what requirements does that prayer leader have to meet for it to be a valid congregation?
Bismihi ta'ala
It is always mustahab to perform wajib prayers in congregation. There are many traditions that emphasise on Jama'ah prayers, and how multiplied the reward will be when conducted in congregation.
With the absence of a qualified religious scholar, there will still be a virtue of Jama'ah prayer. In brief, the person who leads should be known for his piety, and also have knowledge of the rulings of prayer.
And Allah knows best.