It's possible. But no, there is no way of creating pixel perfect collision detection - well... no way for us to script it with the available data structure anyway, as we can't access the character polygons. If we could then I think it would have been possible to use the new isInPolygon() function & a loop to check for when 2 characters polygons overlap.
I guess you could still in theory create a fight sequence by checking the distance of the characters from one another & the active animations of the characters to determine if the attack hit, missed or was blocked.
A quick time event (QTE) sequence would probably be the easiest way to go about it, by having the player have to click specific sections of the screen in time or specific keys on the keyboard.