I just made a major breakthrough regarding the Emerald Textures. There's a way you can use Yoshi's Emerald Texture AND use his Final Smash without having the game freeze. However, you will need SSBBinsert.exe to accomplish this task.
1: Extract the .brres files from FitYoshiDark.pac; they're 000.brres, 001.brres, and 002.brres.
2: Get hold of Yoshi's normal PAC file and place it along with the Emerald Texture BRRES files in the folder that SSBBinsert.exe is in.
3: Open up Command Prompt and go to the directory that SSBBinsert.exe is in.
4: Repeatedly input the command, SSBBinsert.exe FitYoshi##.pac -i ###.brres until you've placed all the Emerald Texture Yoshi BRRES files into the normal Yoshi PAC file.
In the end, you'll end up with a Yoshi PAC file that contains not only his Emerald Texture, but also his wing texture parts, which will keep the game from freezing. The PAC file should use 1,652 KB (1.61 MB) if you did the steps correctly. Just keep note that the wings will not be affected by the Emerald Texture.
Old. I did this ages ago and said it somewhere. Its not really a breakthrough either, its just common sense.