2. Question: Why does the Ohr Letzion poskin that anyone can give a haircut to their 3 year old at anytime of the omer but the bottom Tosfos in Bava Metzia 10b says that not even women can cut off the peus of boys?
A. The negative mitzvah of cutting off peus on a Jewish Male doesn’t only apply to a man but even a woman can’t do the action even to a boy who is not obligated in mitzvos but the women still transgressed the prohibition of cutting off the sidelocks. (See Tosfos there.)
B. The laws of mourning don’t apply to children whether it is for a relative who died or during the 3 weeks leading into Tisha b’av etc.
C. Not cutting hair during the omer is a custom in order to remember the loss of Rebbe Akiva’s students.
Answer: Mourning doesn’t apply to a child at all so anyone can cut his hair even if they are mourning since not cutting hair only reflect mourning which doesn’t apply to the child but the prohibition of cutting off peus is an issue on the cutter not just the one being done to so even if the child isn’t obligated in the mitzvah as of yet but the hair cutter or the one allowing the hair cut to be done is.