As for a feminist angle and Burn being the first feminist entry in the franchise, I feel that the original The Evil Dead can claim that award:
Before The Evil Dead, the 70's were over flowing with terrified final female survivors running from large male maniacs. Laurie Strode running from Michael Myers, the final girls running from Jason Vorhees in the Friday the 13th films, Silent Night Deadly Night, Charles Bronson's Death Wish films, Sally Hardesty running from Leatherface, Ripley in the first ALIEN running from the alien etc etc ...
The Evil Dead came along and subverted all of that.
We were supposed to think Scotty was going to save everyone, What we got instead was a terrified final male this time called Ash who was running and screaming from three powerful evil women, his girlfriend, his sister, his mate's girlfriend ...
So in that sense, The Evil Dead, if we're instead watching it through social studies eyes can be argued to be ahead of it's time. Even when Scotty re-animates as a deadite at the end, he's feeble in comparison and doesn't last as long as a deadite as the women do.
Off the top of my head, the only other horror films that have a female monster kicking everyone's ass are Night Of The Demon 2, The Hand That Rocks The Cradle, MISERY and Peter Jackson's DEAD ALIVE.
In Within the Woods, a possessed Bruce was stalking Ellen. In The Evil Dead, that switched to a possessed Ellen stalking Bruce. A social studies group could ask: was Raimi all about equality by empowering women in The Evil Dead, was the Evil Dead misogynistic and a mirror of 70's western men scared of feminism or are we all reading too much into it and did Raimi just pick the best actors for each role for each story the same way George Romero selected his actors for his films?.