Hello Fafi, as for your teeth they have to be good looking but they don't need to be perfect. You can't have any visible teeth missing, and wisdom teeth should be removed if they can affect your other teeth, this should be evaluated by your dentist, if they grow fine then there is no problem in keeping them.
EK requires you to get x rays so they can see if everything is ok. And as you say you have to have all fillings done.
Braces or even invisalign are not accepted, you have to finish treatment before joining.
Hope this helps!