Just take him to the pediatrician
I mean, there's a groove there and it looks much more sunken in on the first photo you posted. The other photos look normal. You're doing the right thing by consulting the pediatrician to be sure.
I would take him to see a paediatric consultant or actually and oral maxillary facial consultant who specialises in children's head shapes
No that looks normal to me. You can kind of see her soft spot on the top of her head but it fills out/hardens with time.