-It is permitted to cut hair on Lag Ba’omer regardless of which (of the two major) minhag of Aveilus one is keeping, unless one is following the minhag of the Arizal which does not permit cutting hair even on Lag Ba’omer and even for a Bris.
(Shulchan Aruch w/Mishnah Brurah 493:2, Shaarei Tshuvah 8)
-One of the earliest sources for the minhag to go to Meron (the burial place of R’ Shimon bar Yochai) on Lag Ba’omer and light a fire in the zchus of R’ Shimon bar Yochai is from R’ Chaim Vittal in the name of the Ari Hakodosh and Rabbeinu Ovadiah M’Bartenurah. Many have the minhag to bring their sons who are three years old to have the first haircut at Meron and thereby perform the mitzvah of leaving the Peios of the head uncut. This minhag is mentioned by R’ Chaim Vittal as “an age old minhag” at the time of the Arizal. (Sefer Gal Peninim){[email protected]/Matzav.com Newscenter}
