Unlike other people I find the portraits surprisingly diverse, I expected to see very white faces considering most "realistic" representations are from white actors and white statues erase features. Not a perfect project but interesting.
What is odd here is that it's actually likely overdone, as the "blondies" in roman times were unusual enough that they were explicitly noted as such, e.g. Lucius Cornelius Sulla Felix was noted as "his golden head of hair gave him a singular appearance".
We have plenty of colored images from roman times through mosaics.
For more on the painting of ancient statues, see, e.g., https://www.newyorker.com/magazine/2018/10/29/the-myth-of-wh...
Also, later on many were not Italian at all.
Caligula looks as I expected him though.