1) Can you tell me the difference between sunni and shia nikkah?

2) If you belong to Pakistan or India you'll probably know about that "walima" ritual. Is walima a society made ritual? Can walima happen if the couple did not had intercourse?

3)Is it important for the bride and groom to have intercourse on the first night ?

4) Can a shia muslim make a will to donate her body organs after she dies? Is it halal to donate organs after you die?

1-Being a Shia we can’t accept any other way of Nikah but same time all marriages are accepted in Islam according to their own customs and traditions and if they accept Islam no need for them to repeat their Nikah again.
2- Walima is Mustahab (appreciated act if you do will get sawab but if don’t do will not be punished). It has no relation with husband and wife’s physical relationship.
3- It has no restriction it depends on their mutual understanding.
4- It not allowed to make such will for donating ones body organs.