I have 1. grade 2 spondylolisthesis of l5 over l1. 2. mild unequal leg length 3. deviation of nose and have a bit of facial asymmetry. would these be interrelated? would this cause muscle pain in luq?

Probably not: Mild leg length inequality, deviated nasal septum and facial asymmetry are very common. So, those traits are difficult to associate with gr ii listhesis, which is not very common in a young person like yourself. Anterior abdominal pain is unlikely to be related to it either.

Doubtful: The spinal problem could contribute to unequal leg length but there is no connection with nose deviation, facial asymmetry or luq abdominal or muscular pain as far as i can see.