Naruto didn't have the kurama marks on his face while he was just born. Naruto did not have kurama's chakra until kurama was sealed into him as a baby. He didn't have the marks, as his mother didn't have the marks, I think Kurama might have been put under enough control, so as not to let his chakra affect the child in anyway. He only got the marks after Minato sealed kurama in him... But with Both Naruto's children, It's a totally different case, Naruto is not a lady that the seal weakens while she's pregnant, and Kurama is completely free of any seal inside Naruto, which means that kurama's chakra flows in naruto in normal cases now, without even asking for it, it's already there. So, Yes.. Both Naruto's children will definitely have kurama's chakra, not upto the level of Kurama mode.. But definitely up to Sora's level. They will have the chakra in them. They have the marks.. That's the complete evidence that they both have the chakra. And yes they will be able to generate the chakra for battle, and transform to the sora-like level kyuubi, later on Naruto might give Kurama to his son, or split it into both of them, but that won't be happening anytime soon.
And Yes. They could also possess the byakugan. We all know that not everyone that can use the byakugan compulsorily have the white eyeballs, they would probably be able to activate it when needed, and deavtivate it when not needed like the normal byakugan users, just that their eyes won't show that they have it until they actually use it, but... In the worst case scenario, if Boruto doesn't have it, he'd still be able to pull off some hyuga moves, But Himawi would definitely have it.