I'll answer what I can; no, you don't have to provide a COA if you use EBSQ in your listing. You have the option, but it isn't a requirement. And yes, you can use the EBSQ logo in your listing. Somewhere in the sidebar menu on your profile page, there should be a link to different logos you can use. Also, EBSQ provides a handy dandy auction template that you can access right from your portfolio. If you select the item you are going to list from your art case, the "edit item" drop down menu has an option for "generate template". That is a very attractive and easy option, as you just fill in your shipping info etc. and it creates the listing, with legal links and logos, from the already existing photos and info on the piece.
Hope that helps! And welcome!
Change occurs when the pain of remaining the same outweighs the fear of the pain of change.