The domestic goat or simply goat is a subspecies of C. aegagrus domesticated from the wild goat of Southwest Asia and Eastern Europe. The goat is a member of the animal family Bovidae and the goat—antelope subfamily Caprinae, meaning it is closely related to the sheep. There are over 300 distinct breeds of goat.
In the name of Allah
Considering the obligatory Qurbani (sacrificing sheep, goat, etc.) for a Haji (Pilgram to Makkah) in the Hajj al-Tamattu on the Day of Eid al-Adha, every Haji should offer One Qurbani and not less. so sharing it with another Haji won't work.
However, for a Mustahab (recommended) Qurbani, any number of people can contribute and share the Thawab of one Qurbani.
No, it is not necessary or wajib, unless one had made a vow that should they purchase a new house they will sacrifice an animal.
Otherwise, they do not need to. Of course, it is highly recommended to show gratitude to Allah ta'ala, and thankfulness, and to repel envy or evil eye, by organising a banquet (waleemah), and by sacrificing an animal and feeding people. It does not need to be a goat, but any halal animal.
And Allah knows best