I don't think the engine is a problem... id Software released it under GPLv2, and I think you cannot "undo" a such thing.
The problem with "scrolls" was the name (possible confusion between "Elder Scrolls: Skrym" and "Scrolls" tiltes), and was triggered when Notch tried to register "Scrolls" as a trademark. I suppose Fromhell will never try to register OpenArena as a trademark, am I wrong?
Reading the previous thread about that may be useful:
http://openarena.ws/board/index.php?topic=4242.0(and may also be a more adapt place to talk about this problem)
I have no recent news about that story. Does someone have?
I think we may choose a different name for the game, to be used in case of need of an emergency switch ONLY... but probably (and hopefully) we will never need to actually perform that name switch. A name change would cause a big number of problems... I'd do that only if we were really forced to do it.