回复：J1 waive through IGA and EB1-B Greed Card Application

J1 waiver getting from no objection letter, IGA, or extreme hardship are all the one same I-612. So whatever is easier/quicker to you or you are eligible for will do.
Just like GC through any categories (except for those subject to 2-year condition) are LPR when GC approved. Whatever category is easier/quicker to you or you are eligible for, just do one is enough (or more categories if you want, but they all end up with one same I-551)