00 = Mario
01 = Donkey Kong
02 = Link
03 = Samus
04 = Zero Suit Samus
05 = Yoshi
06 = Kirby
07 = Fox
08 = Pikachu
09 = Luigi
10 = Captain Falcon
11 = Ness
12 = Bowser / Giga Bowser
13 = Peach
14 = Zelda
15 = Sheik
16 = Ice Climbers
17 = Marth
18 = Mr. Game & Watch
19 = Falco
20 = Ganondorf
21 = Wario / Wario-Man
22 = Meta Knight
23 = Pit
24 = Olimar
25 = Lucas
26 = Diddy Kong
27 = Pokemon Trainer
28 = Charizard
29 = Squirtle
30 = Ivysaur
31 = Dedede
32 = Lucario
33 = Ike
34 = R.O.B.
35 = Jigglypuff
36 = Toon Link
37 = Wolf
38 = Snake
39 = Sonic
40 = Mewtwo
41 = Roy
42 = Knuckles

Each costume slot is paired up with a 16-bit value XXYY as follows:
XX = team info
YY = costume ID

if XX = 00, Red Team
if XX = 01, Blue Team
if XX = 03, Green Team

Other values are useless and were probably for debugging purposes in Brawl.
PM has several alts that share XX values when not on teams with no consequences known.

When you are finished adding costumes, make sure to add 0C00 to the end of the list of your costumes so that the game does not search for more!

The last true costume values should be no later than 0x62-0x63! The 0x64-0x65 is leeway so that 50 costumes can still have a 0C00 footer.

WARNING!! Do not place any Wario costume ID at 0xF (15), 0x1F (31), 0x2F (47) or 0x3F (63). These break the game if you try to load Wario-Man
from the CSS. There are enough IDs to still give him 50, so simply select a different value instead of using those specific four.