Does reciting Al-Fatiha in a loud prayer with a narration other than that of Hafs necessitate redoing the prayer? And does the presence of ointment residue on clothes after using it to treat an anal fissure invalidate the prayer and prevent one from leading congregational prayers?

Reciting in prayer with a recitation other than that of 'Asim is permissible and does not invalidate the prayer, as long as the recitation is متواترة (transmitted by multiple chains of narration) and authentically established from the Prophet (peace be upon him).

As for the ointment: - If you apply it to the outer surface of the anus, its discharge does not cause harm and does not invalidate ablution. - If you insert it inside the anus, then the discharge of anything from it invalidates ablution. - If it invalidates ablution, you must strive to pray at a time when nothing is discharged from it. - If you do not know a time when it ceases, then your ruling is that of one afflicted with سلس (incontinence): you perform ablution after the time for prayer begins, pray the obligatory and supererogatory prayers, and take precautions against the spread of impurity. - If the ointment exits from the inner part of the vagina, it is impure, and its removal is obligatory before prayer. - There is no harm in you leading the prayer even if you are afflicted with سلس, although it is better to refrain from leading prayer to avoid disagreement.