I think you missed the point of the first line, which is exposing the tautology of saying that the Nika fruit makes Luffy more Nika. Just like the rubber fruit makes Luffy more rubber. Or the phoenix fruit makes Marco more phoenix. Or the magma fruit makes Akainu more magma. It's the premise itself of DFs.
The point I'm making is that we never saw Marco without the fruit or in the earlier days of acquiring the fruit.
That's a different argument than Daz' – and it's a more interesting point. "There's no way to know", so we don't need to assume anything right now. For this chapter, what we know is that Luffy after awakening is still the same Luffy we've followed for the entire series.
About the topic on a meta level, it has always been a thing that Oda crafts characters by matching powers and personality, and that goes beyond Zoans and their 'wills'. All Paramecia and Logia are like that too. Even Luffy was signified by rubber as a symbol of his resilience and the willpower to bounce back.
There's no way to know because we only know of current Marco. And we spent a lot of time with our boy Luffy.
There's no need to consider meta level, when it was strongly implied and even directly confirmed in this chapter that zoans have wills. If zoan fruits can make objects behave like animals, and animals behave like humans, it means there's always going to be some degree of influence on the user. I figure it depends on whether the user lets loose or maintains constant control. I figure Impel Down guards relied on fruits too much and got overtaken by animalistic influence. We saw koala munching leaves, for example.
Here in this chapter we have Luffy state he's having fun for some reason, and laughing differently. Maybe it's an adrenalin rush, or maybe it's the will of the zoan affecting him. In my opinion, we're still not out of the blue regarding fruit's influence on Luffy, possibly Joy Boying him further.