how to show I fit in with the department during faculty interview
The other answer has good advice. But for a job with a research component, I'd interpret it at least partly as "How does your research synergise with our own?".

Point out things that you could work together with existing staff on; areas in which you could help each other out, and things where the combination of your skills/knowledge and their skills/knowledge might combine to produce something bigger than the sum of its parts.

Similarly, but less clearly, on the teaching side you might be able to identify how you fill a gap in their existing areas of expertise.