This promotional picture is the first we've seen Simba and Nala's depictions in the series (Hopefully soon we will see Kiara's design).
Nala's coloring seems to be more based on her Lion King colors:
But she seems to have her Simba's Pride eyes and general face shape:
Simba also seems to be a mix of his Lion King design and his Simba's Pride design. His coloring seems to be based on the first Lion King, but his build and his mane seem more like his Simba's Pride incarnation.