{SOLVED}Transparency is a bid weird

Thanks for your suggestions! And thanks for willing to spent time on telling me things even unrelated to my problem. Embarrassed that I will keep making the same mistakes. About the last problem. Yeah. I know that it is not a good idea to make clothing with loose sleeves in the armpit area (But just can't help to be attracted by some design of clothing. (A smile with the guilty about attracted by design)). Can't help to make another cc with the similar design again. But I already understood that it will cause clipping in game! I will try to avoid the design in the future!

Haven't fixed the problem based on your suggestions bcs in my time zone the day gonna off. I will reply again once I fixed or failed to fixed the problem.

Although my cc making skill is not good enough, easy to be attracted by different kinds of clothing/acc design and want to make them into cc. Wanted to make a fur hat like this. (I know the fur is hard. Just can't help to be attracted) I have read another answer about how to make fur clothing by you in another thread. In that thread took marigold for example. I guess maybe it is marigold's fur coat acc. I studied it blender file based on my shallow cc making knowledge. I feel the fur effect achieved by adding fur texture to may planes. Have studied other creator's fur design a bit. The ear part seems have two layers. Wondering whether it be achieved by create a ear shape. Then duplicate and alt+S to make it bigger. Then add fur texture in the outside shape.

Since my cc making skill is shallow and I have never make fur cc before. Not sure whether I am just bullshit. Much thanks if I can get some suggestions. (eager eyes but no meaning for pushing to replying my question)

Thanks for your reply! Tried to make cc transparent. But have met weight problem when try to use two mesh groups. The fingers wont fly when I use one mesh group. But the problem came out when use two mesh groups. That confused me.

Have tried retopo simple object manually. But temporarily always not do well in retopo. Have lower the tris. Have deleted garments not visible as clean as possible (But can't be really clean since the shorts can be seen when the sim sit down). Made the uv islands bigger. Had chose a reference a bit longer than my mesh. As for transfer vertex painted. Not sure whether I have done right. This is what I do when I try to transfer vertex painted.

package:
drive.google.com/file/d/1QJSBBD4ET_SlzNlDtfD3szdK7qwOePY9/view?usp=sharing

Blender:
drive.google.com/file/d/1Dw64dwLh658rhVI6MLdy_Md0fEXapuAG/view?usp=sharing