Ok, I did the research. For first two weekends, Maya's best year was 09 and Diana was 03. (I haven't researched Breanna, but she tended to save her best for the F4).
Maya and Diana were a bit better in terms of offensive production, as evidenced by a significantly better points per fga. However, Napheesa crushes them in rebounds, turnovers and blocks.
To my mind, Napheesa's numbers are clearly better.
Bear in mind that my original claim was only that Napheesa had the best first four games ever STATISTICALLY. This doesn't account for tons of stuff, like how much attention they drew from opposing defenses, quality of opponents, to what degree they "put the team on their shoulders." I would NOT claim that Napheesa had a better overall performance than Maya in 09 or D in 03. But purely based on stats I think she's a pretty clear winner.
Napheesa Maya 09 Diana 03
Points 24.0 21.8 26.5
fg% 667 638 667
3pt fg% 500 700 500
ft% 750 765 778
pts per fga 1.60 1.85 1.80
rebounds 10.8 6.8 4.8
assists 3.0 3.8 3.3
turnovers 0.3 1.5 2.3
blocks 3.0 0.3 1.3
steals 2.0 2.0 1.8
minutes 31.5 34.0 30.8