The #1 point in 'Things You Need To Know About Eberron' is 'If it exists in D&D, then it has a place in Eberron.' Further along, it specifies the PHB, DMG, and MM in particular, but does that nullify the previous statement?
Beyond that, it's obvious that the XPH was in mind when creating the Eberron setting, although none of the races from the book (or even acknowledgement that they exist) is there.
I guess it's up to you - but regarding one of your points - I think Half-giants would fit more than any of the others. I mean, as long as there are giants, half-giants are reasonable - the others would be entirely foreign (assuming the assumption is that the XPH races are ignored by Eberron.)