I'll save you the trouble.
OriginThat's where those sprites come from, and they were created starting
before Brawl was even released. There's no problem with you guys using them unless you claim you made them, as stated by Abyss Wolf himself.
Clearing this up for the benefit of Abyss Wolf
To add on to this...
The sprites themselves weren't made for PM, but the CSS was, as indicated by the palettes of the recolors (i.e. Minus doesn't have a purple Sonic, but PM does). It's a custom CSS meant for PM.