Well, it may very well have changed, but the (tentative) plan stated during the KS campaign was that if your player character replaces one of the pre-created potential companions, you can change:
A) sex, head & skin
B) class, stats & skills
C) name - unless you're the Red Prince
D) race - as long as it makes sense
Kind of sounds to me like all the origins - other than, of course, the generic one - might've through iteration solidified so far that none of them allow different races anymore, but don't quote me on this.
