Consider someone who was born to a jewish father and non jewish mother who then converted to Judaism with his mother. It seems pashut from the Shulchan Aruch that one who converts is considered a "tinok shnolad" and therefore has no obligation to mourn for their parents. Therefore it seems obvious to me that Aninus is definitely not an issue. The question is that if a convert in that situation would wish to mourn could they mourn and to what extent. The Taz seems to indicated that one may willingly mourn for someone as long as they accept the mourning completely and do not transgress any negative commandments in the process. Does anyone have experience with this type of issue?