Setting variables, hypothesis and analysis

Hi guys, I'm an engineering student. I only have certain knowledge in statistics analysis. As I doing a research on expert survey on human in the loop input selection for maintenance model. so I've came up with 8 inputs. I would like to test out all the inputs to see which inputs are suitable to develop maintenance model by asking questions and obtaining the opinion (likert scale) from experts.

Ive set the inputs as dependent variables but I do not what should I set for independent variables

also for my hypothesis, as I wanted to test out which input is useful for the maintenance model. what should I consider for null hypothesis or alternative hypothesis.

last question may I know which analysis is suitable for such research