There was also an enormous amount of scalping and collecting of Japanese body parts done by Anglo soldiers in WW II. The most famous case was a Japanese skull sent to a white Marine's fiancee, which made the cover of Life magazine. FDR also got sent some Japanese body parts as gifts from a serviceman. He was appalled and threw them away.
What you describe in the film much more resembles the second case, collecting body parts for trophies or doing it to intimidate the enemy. Kiowa and Pawnee scalp dances are done by women to reconcile the spirit of the dead warrior with that of the man who killed him. The same reasoning is behind Navajo scalping, where it's actually the sideburns that are taken, not the whole scalp, and are burned in a ceremony done by the man taking them. I should also add this was not a widely done practice. The Navajo have very strong taboos about viewing or handling the dead, so most Navajo soldiers never did this.
The single case I know of where a Cherokee soldier (actually an officer) scalped German soldiers happened in Italy. He was part of an elite commando unit. The unit ambushed a German patrol. The officer decided to scalp the dead patrol members and leave them sitting by the side of the road, arms neatly crossed, unhelmeted with the bloody heads on display. This was done to intimidate and shock the enemy.
When I first read this account, I thought the officer may have known about Germans' love affair with Karl May books and all the falsehoods in them. In WW I some German commanders actually ordered their snipers to kill Indian soldiers before white ones when possible. There were some articles in both US and German papers where German soldiers were said to be fearful knowing that they would be facing Indian soldiers, fears likely provoked from reading those same May novels.
I don't know of any widespread use of scalping by Cherokee soldiers, or indeed by Cherokee warriors. I did find some accounts where the British, in fact, scalped many Cherokees during their colonial era wars with them.
Cherokee Confederate soldiers were also widely accused by northern newspapers of having scalped Union soldiers. But I couldn't find any evidence to corroborate that, so I consider it wartime propaganda or sensationalism.
You're right that Apaches were far more often the victims of scalping than the ones doing it. Sonora, Chihuahua, and Sinaloa all offered bounties for Apache scalps, which were collected not only by white and Mexican bounty hunters, but by a company of Shawnee, Seminole, and Tarahumara mercenaries called Sahuanos. The O'odham also collected Apache scalps, which they kept in baskets.
BTW, I looked up Tarantino's supposed half Cherokee mother. It made me suspicious, since Cherokee (and Indians in general) generally don't refer to themselves half this or quarter that when identifying, but simply as Cherokee, etc. Tarantino's website says "half Cherokee" but many other sites say "part Cherokee." That includes his own Facebook site.
Quentin Tarantino--Film Director, Actor, and Screenwriter
Tarantino also grew up in Tennessee, where seemingly every white claims to be "part Cherokee." It's long been my opinion that most white Southerners with a story of a Cherokee in the family history were actually told that by family trying to explain away a Black ancestor. I don't know if that's the case with Tarantino. I do think that if his mother were actually Cherokee, he'd have been raised to tell people, "I'm Cherokee" rather than the usual white Southerner claim of "I'm part Cherokee."
There have been a lot of Native soldiers in movies, books, and comic books. Usually they're stereotypically good at hunting, tracking, and killing people. Usually they don't scalp their victims.
For more on the issues raised here, see Defining Who's an Indian and Indians in the Military.
Below: Little Sure Shot from the Sgt. Rock comics.