Futo
1. Disembowels her opponent by slicing her abdomen with a plate and then lets the small intestine pour out onto it. After disconnecting the intestine from the body using another plate, she uses the latter to cut off the victim's head and then puts it on top of the plate of intestine, as if presenting the whole thing as a dish ready to be served.
2. Readies three burning arrows on her bow and fires them at her opponent. One hits the forehead, another one hits the throat, and the third one hits the chest. The victim falls down dead on her back while burning up.
Byakuren (none of her fatalities involve blood in order to reflect her distaste for violence)
1. Places her hands together and chants something to make herself give off bright light that disintegrates her opponent completely.
2. Jabs her opponent with her hand very fast multiple times. Nothing seems to happens at first, but then the opponent gets a heart attack and dies.
Yuugi
1. Grabs the opponent's sides and then pulls it down so hard that the lower torso "sinks" into the upper torso. She then pushes the victim's head from above into the body. The victim is now a headless upper torso with a pair of feet at the bottom. She then kicks the whole thing away (the head-pushing part is inspired by one of Goro's MKX fatalities).
2. Punches the opponent in the body so hard that it flies back, leaving behind only the head and the limbs, which fall to the ground.
Yuuka
1. Makes a flower grow from the ground and then picks it up along with a small batch of earth. She then rips off the top half of her opponent's head, cleans out the inside of the brain, and then plants the flower inside it. While the opponent is dead in a sitting position, she waters the flower with a watering can.
2. Makes a stalk grow out from the ground to stab the opponent, carrying her into the air in the process. The victim explodes afterwards, and a large flower is seen in place of where she used to be. The truth behind this fatality is that the victim got stabbed by a flower bud at the end of the stalk, and when the bud bloomed, it ripped her apart.
I use feminine pronouns to describe all my victims because I imagine the fatalities being performed on other Touhou girls.