Titles, descriptions, prices, tags, details, SKUs, inventory, variations, and photo/video URLs. Optional fields for Etsy listings are not included as they cannot be imported via CSV at this time, but they can be edited in bulk once the imports are complete.
Yes. Download a CSV template for new listings by clicking "Import" from the main dashboard. In an exported CSV of existing listings, add a new row for each listing you'd like to add. Leave the Listing ID column blank, and Vela will treat the row as a new listing. See the video on CSV Import and Export for details on adding listings with variations via CSV.