How can the jurists' two opinions on justice and equality in gifts to children before death be reconciled: absolute equality between males and females, and the male receiving the share of two females? And is the view that differentiates between them based on the son's residency and expenses correct?

This detailed explanation—if its attribution to some scholars were proven—would reconcile the two opinions, but no origin for it has been found. The scholars who mentioned the difference of opinion on this issue, such as Ibn Qudamah, only mentioned the first two opinions. If this statement's attribution to a recognized scholar were proven, then it would be permissible to act upon it, as the issue is subject to ijtihad (independent reasoning) and there is no explicit text regarding it. And Allah knows best.