Hi There
As you can see - I am very much a newbie but I have managed to include the 'About Me' information in my new listings. I think you set up the info in your Master Profile and then it appears in all subsequent listings.
I also set up my "About Us" page in my Auctiva Store.
I'm afraid I dont know anything about the differences between EBay and Auctiva checkouts
All the best
Gill