My cousin passed away yesterday. Since then we have fought nonstop day and night to prevent her body cremation scheduled for by her non-Jewish attendant and guardian. However unfortunately, we did not manage to stop the guardian from doing it her way. I have started, as a Nedava B’li neder, to say kaddish, Mishnayot, candles. Which practical  differences exist between this case and common Chiyuv cases, apart from the mandatory mourning restrictions upon Chiyuvim, and the priority of Chiyuvim, if such are present, to be Shliach Tzibur? 

 

One who is cremated by their own choice is not mourned nor is Kaddish recited for them.

However if it was not by choice or they did not have a proper Torah education, Kaddish should be recited as well as all Halachos of mourning.

However if there is another Chiyuv he should have priority to lead the Tefilos.

 

Sources:

ראה שו”ת חתם סופר אבהע”ז ח”א סי’ סט ובשו”ת מנחת אלעזר ח”ב סי’ לד