How do I use them? My game froze at the result screen. Is it because they're also the select screen portraits?
The portraits that are used on the results screen are in a series of files that are separate from sc_selcharacter.pac or common5.pac.
The files are named, MenSelchrFaceB###.brres, and are not compressed. You need to place them in the directory...
[SD drive]\private\wii\app\RSBE\pf\menu\common\char_bust_tex\MenSelchrFaceB###.brres