can't answer 1. Support should be able to answer that question. Mouse over HELP in the TOP right and file a case.
2 and 3 Yes you can list with Auctiva and ebay will apply the proper fees (or no fees). Please note the estimator will still show the fees
4.. shipping seems to work fine. again a Support Ticket will get you a better answer but basically you can setup a profile and say where you ship and what all the charge are and than when you list it will pull that info into your listing. This was the condensed version of what needs to be done so if you are in doubt how Support is you best option