连襟：Co-brothers
妯娌：Co-sisters

Those are the correct terms unknown to most people.

We all know that both sister's husband and brother's wife are in-laws, so are wife's brothers and sisters. In stead of calling 弟媳弟妹內弟內姨妹婿妹夫大舅子小舅子大姨子小姨子, how do the 江浙一带的农民 call the common in-law relationship, big shot?