I Believe that shouldn't be a problem, you should be able to move all your characters and if you feel like purchasing new slots up to the max of 22 it should be fine. If by the rare chance its not then at least you wont loose any of your characters you will just be limited to the amount you have till they fix the bug which shouldn't be a terrible thing because that would be a bug they would fix. So if it is a problem its not one you would have to put up for for long but as i said i don't believe it will be a issue for you i have 22 character slots and moved a good 18 toons and i am able to create new toons if i feel like it and am having no issue so you should be ok