[Advaita-l] QUESTION ON THARPANA&SRADHA

[ravi chandrasekhara]

Pranam to all,
As Pitru Paksha is approaching, I have some questions. Fortunately as my parents are alive, I do not need to perform any rituals.
Questions for Shan Nava (96) dates.
1.Is only Tila Tharpana performed ?
2.What about homa ? Should that be performed on the 96 days also ? Or only on annual death anniversary of parents ?
3.What if one cannot (due to occupation, school, etc) perform at alloted time after Madhyanika or even the concession time during Sanghavi kala ? May Tharpana be perfomed in succession after Pratah & Madhyana SV and Brahma Yagna; all during prataah kala before 8am ?
4.If mother is not alive but father is living; what should be done ?
I have seen variability and non-conformity with shastras by family members, hence these questions.
Dhanyavaada,
Ravi Chandrasekhara