Does the Rav view the giving of gifts to children on Chanukah as a violation of chukas goyim or simply a practice which has no source in halacha?
Giving presents on Chanuka certainly does not violate the prohibition of Chukas Hagoyim. This prohibition is only for customs that have no plain logical reason. Giving presents at a festive time is a logical and therefore permitted act. The Magen Avraham [O:C 670] mentions a custom for children to collect money during Chanuka. Various explanations are offered for this practice, but the basic idea is that it is done to bring simcha and to create more פרסומי ניסא. On the Shalosh Regalim one is obligated to buy gifts for the members of his household. While we do not find this obligation by Chanuka, perhaps it is inthis spirit that some have the custom to do so. Some Rishonim infact explain that the 8 days of Chanuka are based on the length of our longest Yom Tov, Sukkos.