Definitely, though I'm not sure if Zeref would be in the required state of mind, which is why I ruled it out.
It depends a lot, fights with Zeref can never last too long in a fight case there´s the possibility of him unleashing his curse out of nowhere and remember in Tenroujima arc when he tried to keep calm for years upon years only to use up his curse again 2 times in the spam of a single day case people tried to fight him and force him to do stuff he didnt want?
Also I think Zeref can do a decent number of spells himself, (probably way more than Jellal (and some like Abyss break too)), I wonder what was the magic he had before he got the curse and all.
But eitherway, Laxus cant eat anything thats not lightning, and even if he pulled a Natsu and tried to eat another element, he wouldnt be able to eat the other magic elements Zeref can pull afterwards, it´s gonna turn into the whole August vs Natsu, or God Serena vs the other 7 dragon slayers, where the winner should always be the one with more quality and high magic power (Zeref might have infinite magic power), so he automatically wins by default against Laxus.
In matter of fact, Zeref will one shot Laxus eitherway, really, either he loses his cool and finishes him off with the curse, or he goes full cold-blooded and uses his stronger spells to face Laxus (which he might still have in store for his future fights).