I think people did read every bit into the osx thing though. The average user after hearing the words "it runs osx" were blown away, nobody was aware of any other form of osx, which is something Apple didn't inform us of. It's just bending the truth, massively. All they had to say it was a stripped down version of OSX, or a baby OSX. But branding it with the same title to generate more hype and ultamately more sales is a bit cheeky.
As I far I know, iPhone runs OSX, not a baby version of it.
There are some OSX interface features that are available on the Mac and suit its form factor, but are not available on the iPhone. On the other hand, there are some OSX interface features that are available on the iPhone that suit its form factor, but are not available on the Mac.
Someone could equally make the case that it is the Mac version of OSX that is the baby compared to what ships on the iPhone. But that would be equally wrong. They are both OSX, with different interface features optimized for their respective form factors.
Beyond that, I think it's reasonable to expect cross-pollination over time, and Apple has publicly hinted as much. But underneath the interface is OSX, not baby OSX.
I totally understand regarding would a multi-touch screen on something so small be even usable, and of course it wouldn't, you only need dual touch. It would just be nice to see Apple say this rather than multi, if indeed it is only dual. If it is multi touch, then great! but if not, then say so, put "dual touch"
Well, we don't know! There may be some future gestures that require three fingers and tap into the device's capability to accomodate that.
There may be limits to the hardware and software (and they may be different) regarding how many simultaneous touches the device can accomodate. It may be two or it may be two thousand. Or maybe there are no limits, and the device will spark an evolutionary increase in fingers...
However, your interest is semantic: why call it multitouch instead of dual touch? Aside from the obvious - that it may not be limited to two touches (we don't know) - multitouch not only sounds better than dual touch, but also substitutes for it. Interestingly enough, "multi" has multiple definitions, one of which is "more than one". "Multi" need not start at three, and even if iPhone were limited to two simultaneous touches, that can be legitimately described as "multitouch."