What is the ruling on kissing a young girl out of mercy and not out of lust while fasting, and what are the sayings of the madhahib regarding this, along with the evidence?

Kissing children out of mercy and compassion is permissible and a Sunnah, and there is no difference in this between a fasting person and others. The Prophet, may God’s prayers and peace be upon him, disapproved of those who did not kiss their children, saying: "He who does not show mercy will not be shown mercy," and "Or can I put back into your heart what Allah has taken away from it of mercy?"