(1) You can of course apply for EAD. THe comapny laywers most likely won't know this. Why do you care?
(2) Current EAD filing fee is $340. (Wow).
(3) Just download I765 form here abd following instructions step by step:
http://www.uscis.gov/portal/site/uscis/menuitem.5af9bb95919f35e66f614176543f6d1a/?vgnextoid=73ddd59cb7a5d010VgnVCM10000048f3d6a1RCRD&vgnextchannel=db029c7755cb9010VgnVCM10000045f3d6a1RCRD
(4) Don't know how.
(5) You don't have to re-apply. The priority won't be carried to your case if you do.