I am confused

Can anyone explain me,

Bittu and munni are in their mission of finding Tauji's murderer, but why they are showing all this amritkhet wala part. I mean what is the relation of Tauji murder and binni past.

also if bittu and munni were lover from last birth and the secret is related to this bro trio is hiding from munni then how can they are not aware of bittu. like they were lovers from last birth then they should not even let munni go near bittu.

please someone explain.

m very confused