This filler takes place before the war ever started and that's obvious. I am actually really enjoying this filler. But I will agree that Edo Hidan does not make sense. The reason he was not revived with the others in the canon series is because he is still alive, and you can't Edo Tensai a living soul. So that's the only part of this I don't like.
I understand why they decided to make this ridiculous come-back though. Hidan was a very cool concept for a bad guy and had an awesome scythe and didn't get enough air time as all the other Akatsuki members since he wasn't revived by Edo Tensai in the war.
for 3 weeks now i've been wondering how the filler fits in anywhere? is yamamato caputered for 1 isnt there a war going on for 2 and why on earth if 1 and 2 are true would they stop the war just to go on a side mission???