LB: There is a prohibition about “wasting things” especially food known a BAAL TASHCHIS”. He stated that if you have food that you consider assur then you are not violating BAAL TASHCHIS by throwing it out.
As for shalach manos, lets say you give someone 2 pareve items and 1 chalav stam, you were yotzai the mitzvah with the the two pareve items. It is practically impossible to know everyone’s personal chumros. What if a person doesn’t eat from “Hashgacha A” and all your items are from that hashgacha? Do you have to worry about that? No.
As for giving food items to a goy, he stated it was better to give it to someone you don’t know.
I have friends who are makpid on chalav yisroel but their children aren’t. They just give the chalav stam to their children.