I know that there is a custom to get an Aliyah and give kiddush the Shabbat preceding a yaharzeit. Does this apply to the first yarhzeit as well, when the person is still in availus-assuming the deceased is a parent?
Nitei Gavriel Aveilus2:69:1 says that one should Daven Musaf the Shabbos before the Yarzheit even if he is still in the year.
On page 528 - 69:5 he brings from the Levush, Magen Avaraham 282:18, Minhagim Vermaiza 35, Shaarei Efraim 2:67, Kitzur Shulchan Aruch 78:11 that one should get an Aliya the Shabbos before the Yarzheit. There is no mention that it should not be done in the first year.
Don't know in regards to a Kiddush. Many people only give a Kiddush on Shabbos if the actual Yahrzheit is on Shabbos. If not they give tikkun on the day of the week it falls on.
The German minhag is to only get an aliyah if the day of the yartzheit falls on a Torah reading day, not to get one the Shabbos prior. Some have the custom to get one on the Shabbos prior if the yarzheit falls on a day when the Torah is not read. IE if the yarzheit is on Tuesday (that is also not a Rosh Chodesh etc) then one would get an aliyah on Shabbos, but if the yartzheit is on Monday then one wouldn't get an aliyah on Shabbos. Some try to get the aliyah both times, on prior Shabbos AND the actual day of the yartzheit if it falls on a Torah reading day.
1I don't see how this answers the question– Double AA ♦Jan 3, 2022 at 20:25
being the first yartzheit would for sure not impact getting an aliyah or not. It might possibly impact making a kiddush. My mother's first yarzheit fell on a Shabbos and I made a kiddush and got an aliyah but I did not lead davening since aveilus was not yet over since that goes by one year from the burial, not one year from death, and typically one does not lead davening on Shabbos if they are in aveilus. Jan 4, 2022 at 15:34