In case anyone's interested/curious, Just thought I'd mention that I finished this project a couple weeks ago. All in all, it was pretty easy. The simplest film was the Half-Blood prince (no work required) while the hardest was definitely Deathly Hallows part 2.

Contrary to what you might expect, not one plot-essential scene was rendered incomprehensible by the editing. For the final battle of Deathly Hallows 2 (which posed the biggest challenge), my task was made easier by the fact that the fighting takes place on multiple fronts. The Harry-Voldemort scenes were able to be left intact, and during the Ron-Hermoine-Nagini sequences there were sufficient reaction shots without the snake visible that I was able to leave untouched, thus creating something of an interesting "strobe light" effect and allowing the action to be trackable.

Thanks for the ideas and input, everyone.