Terms for "white man"?

[Rory M Larson]

I'm wondering about MVS terms for "white man".

  Da:    was^i'c^uN   (nearly synonymous with wakhaN',
                          according to Riggs.)

  OP:    wa'xe        (wa-axe ??  axe = ??
                          [x] is the voiceless form here.)

  Osage: iNs^ta'-xiN  ("yellow-eyes", according to La Flesche.)

What other ones do we have?  I'd be especially interested in
Iowa, Oto, Hochunk and Kaw.

Can anyone suggest a derivation for the OP term?  I think the
explanation given in Fletcher and La Flesche (p. 81-82) is
fanciful.  I was tempted to think of axe as "cry out for"
something, e.g. war, but this verb has the voiced form of [x]
according to Dorsey; thus ag^e, "cry out for", vs. wa'h^e,
"white man".

Thanks,
Rory