i need help "making mesh groups/cuts" & fixing bones/weights

There is no need to make a third thread about the same issue, just post in the old one and it will be updated

The package you shared is still started from something that has no skirt vertex groups, yet the blend file still has them. I explained how to properly transfer weights twice

I also explained that the finger distorts because you transferred weights to a mesh with fingers that are too close to each other. The solution is to simply frankenmesh hands. Judging by uvs, you have not even tried it
I also covered why items are split into meshgroups and how to understand whether you need to split yours. Is the reference you're using made of more than one meshgroup? No. Then why do you think yours should be? Does it clip into accessory or shoes? Does it have transparency? No

How to split the item into meshgroups:
- Download this addon. Type 0 and click Purchase, it's free. Put downloaded file in Blender\2.78\scripts\addons. Install it ( File - Preference - type remove in the search bar - enable the addon - Save user Settings - restart Blender);
- Append the reference. Rename each meshgroup to its cut number for convenience ( ref_0000, ref_0001...);
- Hide all appended meshgroups but ref_0000. Select your item, switch to Edit mode, disable Limit selection to visible. Holding Ctrl to activate lasso selection, LMB-click and drag to select the area of the mesh so that it matches the ref_0000 meshgroup. Press P and choose Selection. Rename the separated meshgroup to 0000 and change its cut number to 0000;



New package

Do everything just like you did in this post. Just frankenmesh hands after that like you would with any part of clothing

This part is how you split the mesh

anyway, it's hard to understand your responses. but i think i figured everything out because the paragraph above is very hard to understand.
 - and i know the dress doesn't have mesh groups but i made another mesh that does. 

here's the link if you want to check it out. i'm pretty sure i did everything correctly. i already had the add-on installed.

i followed everything to the T ..there's no way you can say i didn't now - with the dress. but i still stand by the pantsuit not having forearmtwist in the reference mesh, therefore not in mine.

for the dress- but i did add new hands - so you should've noticed that right away. you told me to frankenmesh new hands, so i did.. i took them from the sweater..at the wrist and i merged them with the dress..i'm kinda sad you didn't even notice... so if you didn't notice the new hands, does that mean the original problem wasn't even started with the hands like you thought? just because you didn't notice the new hands i'll do it again... i completely re-did the dress. check it out here

in the suit-i used the vertex group add-on on the suit and tested it in the game and i thought it looked great also. when i separated the groups and clicked remove groups, it did exactly that - i couldn't get it to work at first but i realized something changed the cut numbers back to 0000 for all groups, i had to re-append the ref and reassign cut numbers. once i did that, the pantsuit worked in game. i double checked the assignments between my mesh and the ref mesh and my mesh has all the correct assignments, the legs basically has b__L_Foot__ b__R_Foot__ , b__L_Calf__ , b__R_Calf__ , thigh and other leg areas. i was excited when i made it to the end, i thought i did it right? because the reference mesh didn't have any forearmtwist assignments in the mesh groups? i just double checked and the reference only has forearmtwist in s4studio_mesh_3 .. is there a reason i should add an extra group to my mesh?  here's pantsuit

1-
2-
3-
4-
5-
6-

you're also right about the forearmtwist, i don't know why i didn't see it originally. it's in the cloned original mesh. that's my mistake, so i added it to every mesh group except 0003. and as for the dress like i said up there, i followed your video to the T and i had a few people test it from tumblr since my meshes seem to look different for me than they do for other people.

i even got rid of shadows on the bottom suit, i'm happy you told me about edge splitting. these are the final products - i did everything you suggested. 🤞

final dress
final suit

Hm, interesting thing. Usually people share their blend and package files, so i don't actually see what the blend file looks like after s4s does it magic on it.
If you were to export the blend file from the dress package, you'd see that skirt and foot vertex groups are still in the list but have no influence on the mesh.
And if you were to export the suit, you'd see that s4studio_mesh_1 has all vertex groups while s4studio_mesh_2 and s4studio_mesh_3 have only those they are influenced by + b__R_ForearmTwist__.
So it seems that once you import the blend file in the package, whatever extra vertex groups the blend has are added to the list. These vertex groups will be added to whatever you import in the same package again, but only to the 0000 meshgroup?
Anyway, for the sake of interest I suggest to leave the packages as they are and wait if anyone will report any distortions. For the future, just keep that in mind

No. First, everything depends on your garment but there is a preferred order.
Second, what we've been discussing in this thread should not be done at all. This was about fixing mistakes that could have been avoided. If you are experiencing the same issue, then of course after the weight transfer, which is what caused the problem in the first place.

The order:

-  closing holes (if there are any); 
- creating a uv_1 map;
- removing doubles, (you must do it before or after weight transfer because even if vertices share the same coordinates, they might get different weight values);
- transferring weights;
- vertex painting;
- removing all parts of the body covered by clothing (if applies);
- editing a uv_0 map (if you will not use the reference as the body, this step can be done at the beginning);
- splitting sharp edges;
-joining the body with the garment;
-splitting the mesh into meshgroups(if needed);
-assigning cut numbers;
-importing in s4s;
-checking in-game;
-baking and editing textures;
-making lods.

This is the most reasonable order for adapting garments made in Marvelous designer, from scratch in Blender or converted from different games. If you are editing a maxis garment, some of these steps are already done. 
Anyway, you can do weight transfer before or after uv maps or vertex paint, but you should make sure that the mesh is not split anywhere. But if you are transferring a uv_1 map, mesh being split along seams will benefit you.