1) No, there is no way to pick and choose which metadata you extract from the ebook file.
2) Yes, you can use the Bulk Metadata Edit, third tab (S&R) to copy metadata from one field to another (or overwrite the
same field). Plugboards are only for certain fields, if you want the
exported copies to have autogenerated metadata e.g. series info in title.
Do you have anything particular in mind? (Hint: details
)