That project looks more like a BZ2 makeover, that's why no one here didn't even blink. 1.5 is as close as it gets to BZ makeover.
As for BZ legal issues, it isn't much different than with any other game. BZ status is just more complicated due its rights being torn between Activision and Atari, but since none of those companies is making money out of BZ anymore, there's a rumor they won't object unless someone else is making money out of it.
You can always lie like reaper does and say that you have a written permission to mod and distribute the game.
http://www.battlezone1.org/permission-t1118.html