Nagato's parents: Just because they have high stamina and life force doesn't mean they have higher chance of survive being stabbed.
Yahiko: Its nothing but a detai... He had to die anyway.
Bee: We're at the climax of the story, there're priorities. Its not like there's time to mourn for the dead during war anyway. Once Madara gets his ass handed to him everyone can bury their loved ones and cry in group.
Neji: This one was just badly executed. Kishi wanted drama and puff... Neji died. What makes it worse imo is that Neji had two bigger holes in him vs Kidomaru and was still alive sometime after, but died so fast to a few wooden sticks planted in his back. Go figure xD
Hashirama: Its unkown how he died, no point in speculating.
Tsunade: In real life, its theoretically possible for a human survive being bisected. This is a drawing, not a major stretch imo and on top of that she's the best medical ninja.
She was in the process of healing the whole time after she summoned Katsuyu, but everything was happening slowly because she had other four people half dead being healed too.
Senju DNA had nothing to do with Tsunade surviving and Hashirama dying (its not even known how he died...).
She might've been able to regain consciousness because of her Senju body's strenght and Uzumaki stamina and life force, but she's alive thanks to her medical ninjutsu.