Which of the two is more deserving of leading people in prayer in the Musalla: the smoker with a shaven beard who has a beautiful voice and recites the Quran proficiently, or the non-smoker with a shaven beard who does not recite the Quran proficiently?

The default rule is that the imamate of every sane Muslim is valid, as long as his own prayer is valid. However, prioritizing people of knowledge and virtue is more befitting. If two imams are equal in sin, the preference between them is determined by achieving the objectives of the imamate and the benefit of the prayer. The one who is skilled in recitation is to be put forward obligatorily, even if he is sinful, over an obedient person who impairs the recitation of Al-Fatiha. If they are equal in recitation skill, the one who is the best reciter of the Book of Allah is preferred, then the most knowledgeable of the Sunnah, then the earliest in emigration (Hijra), then the earliest in accepting Islam (in age). If they are equal in all of these, the more righteous and less sinful is preferred. A smoker is more entitled to lead the prayer than someone who shaves his beard, if they are equal in the qualities that give preference. However, if a mosque has a regular imam, he is to be prioritized absolutely.