To obtain the extra outfit for both KOS-MOS and Momo, just simply find them.
*** These two outfits are only in Xenosaga Episode 1: Reloaded. Unlockable How to Unlock Archetype KOS-MOS It's located at the A.G.W.S Hangar in Woglinde. Kirschwasser Momo It's located at the third tower in Song of Nephilim.
Boldfaced for emphasis. Ep1 reloaded was a Japan-only re-release. --- - Vilurum Xaren, leader of the happy turtles, and knowitall. ... And if you can't spell "Vilurum", call me "Vil". :)
how was i supposed to know that this wasn't a nickname for the english release?
Click on the "Data" link along the navigation bar for the game (between "Home" and "FAQs"). That will show you all the various releases of the game, as well as which regions they were released in.
Precisely one of them has "Reloaded" in its title. The associated region is "JP".
The More You Know™
(Also just as a common-sense sort of thing, if something is specifically designated as being "ONLY" in a certain version of the game, it's safest to assume that unless you specifically know that your copy is indeed that special version, it's probably not.) --- - Vilurum Xaren, leader of the happy turtles, and knowitall. ... And if you can't spell "Vilurum", call me "Vil". :)