Thank you @Gilahu !! 
I read your advices, and I feel they are very effective! 
The opinions I can offer are as follows. (Conversely, I agree with most of the others, so I’m considering improving them)
As for Feet, this is intentional.
It’s natural to feel uncomfortable because this connection is unfamiliar “for BIONICLE”, but I also have other action figures in my collection such as S.H.Figuarts.
What I have gained as a result of this experience is that each character requires a different range of motion, and a common joint structure is not necessarily better.
Her weapon is a sword, and when posing with a sword (example, swinging), the most important thing is “stepping on it” and “center of gravity”, and in this case, the figure needs “an ankle that can move sideways and widely”.
The disadvantage of the “common” BIONICLE foot is that while it has a wide range of motion back and forth, it has a narrow lateral rotation range, which prevents the figure from taking a strong step when the legs are spread wide.
(As you can see by actually moving your ankle, the human ankle does not move back and forth very much. Most BIONICLE feet rarely use their full range of motion, which is almost 90 degrees. So I choose this method for Tuyet )
And about sword’s Thornax launcher pieces is, yes.
But they were originally designed to be pressed and deformed (deliberately stressed) by the finger to fire the Thornax, so they are made softer than other parts and very hard to break.
There was no other way to do this, but I adopted it because I wanted to demonstrate this "softness that makes it possible.
But Thank you many advices! 
I noticed after being warned that her thighs in particular were getting too thick.
After all, I realized that human need to get a good night’s sleep to function properly… 
Now I have to fix her, after sleeping… 
Thank you @Huemus !!
About her shoulder, I think it has enough stable.
As you can see, it’s a little shaky, but she can hold the sword steady and it won’t fall off naturally.
(At least it has strong more than original Krakua’s shoulder)
About forward and backward movement, I’ve already said.
But thank you for your advice!