This is what I know. Kunai specific name cha jasto lagdaina malai.

mama, thulo ba, sano ba, kaka          Sap uncle english ma.  (for more clarification you can say he is my uncle.....brother of my mom)

Maiju , thulo ama, fupu, kaki          sap Aunt

Bhaijo, bhatiji, bhanji, bhanja         sap Nephew or niece

kaka ko chora, thulo buwa ko chora, chori.......haru        sap cousin