So long as copyright isn't one of them, it's all good.
Brendan -- after asking some fellow screenwriters, I got a reply back that while the film may be public domain, Romero's original NOTLD screenplay isn't. You can write a remake script, but only as a piece of fan-fiction. Without the rights, you can't option or sell your script. In other words, if you make one cent off your remake script, you've violated copyright.
This makes sense when you take into consideration the fact that to date, only Romero himself has filmed a remake. Why? Because he wrote and owns the rights to the original NOTLD screenplay. Any other version of the film by another filmmaker has been an altered or re-edited version of the original film. You can literally do whatever you'd like to the original film and release it and make money from it without violating copyright, but you can't actually adapt the original script and create a remake without the rights to Romero's original NOTLD screenplay.
Hope that clears it up for you.
Last edited by LoudLon (2013-05-15 13:38:21)