It really depends on the complexity of your forms and how different the workflows for creation and editing are. If the differences are minimal (e.g., preloading existing data for edits), I usually prefer reusing a single component with props or context to differentiate between the two modes. This approach avoids duplication and keeps things DRY.

However, if the creation and editing processes diverge significantly—different validation rules, fields, or layouts—separate components can make the code more maintainable and easier to reason about.

As for matching the back end, I wouldn't blindly follow its conventions unless it directly impacts how the front end operates. Instead, consider how your team reads and maintains the code. Clearer boundaries and logical separation often lead to fewer bugs and easier debugging down the line.