Questions about Shias?

1) What are the differences between different branches of Shiism?

For example, how are Zaidi, Jafri, Twelver, Alavi and Ismali Shiasm different from one another?

2) In general, do Shias from a particular Shia branch (example Zaidi) consider other Shia braches (for example Ismaili) to be Muslim? How about in their scriptures?

This is for general knowledge only. Please do not answer something that denigrates Shiism as a false sect or glorifies Shiism as the true sect of Islam, as this is not what I'm asking.

Also, please don't tell me how Islam discourages sectarianism as this is also beyond the scope of this question.

Much appreciated.