Hi- if I am understanding you can import all of your ebay listings to auctiva.
HOWEVER, you mention auctiva FREE TRIAL. That trial is to start using auctiva listings services, photo,etc. HOWEVER that does not mean you get to put them on ebay free. You will still be charged ebay fee to list and end of auction fees.
On auctiva you will have great templates to use, you will have place to store you photos if you want. You can schedule your listings if you want at no additional charge (ebay charges for that).
TO me best feature is you can put lots of photos inside the listing without paying for extras. AND, if you sell seasonal items, say Christmas, as long as you pay your fees to auctiva after free trial. You can end them on ebay and auctiva will hold them for you until next year.
Hope this makes sense.