The "quality of life in Oxford generally" is really dependent on who you are, what you need, and what you do. It's a small, isolated college town, an island of wealth in an otherwise pretty impoverished state. This leads to both positives and negatives. There are many cultural activities despite the size of the town, which is nice. The culture is car-centric, which can be frustrating if you don't drive. If you want to ask more specific questions, I'm happy to address them.
As for the relationship between English and Department of Writing and Rhetoric (DWR), there is some collaboration between departments. Literature graduate students and MFAs usually end up teaching composition or working in the Writing Center at some point for the DWR. Graduate students are also part of teaching circles, committees and other professional development activities in the DWR if they wish. That being said, the DWR is still new, so English and DWR still negotiating their relationship with one another, but you will rarely see evidence of that.
The librarians are fabulous. Every single one of them. They are great about ordering books if they're not in the stacks and faculty think they ought to be - at least our department's librarian was. They're all helpful, collaborative, and do all they can to support your teaching.
If you ask more specific questions, I'm happy to address those. Best of luck with your moves!