1.
Most-favoured-nation does not mean treating all corporations equally. A government can
reward or penalize corporations, but the same criteria for doing this must normally apply
to all foreign companies. (There are some constraints on what those rules might say.)
2.
Policies for hiring local staff, using domestic materials or encouraging sound
environmental practices are definitely not outlawed. However, countries have negotiated
terms for allowing their professionals and other workers to work abroad. If they allow
foreign workers in, it is because they want to learn from foreign expertise or they want
their workers to be able to work abroad in exchange. This is not a principle of WTO law,
but something countries (developed and developing alike) want to negotiate with each
other.
3.
The value of infant-industry protection is debated. However, developing
countries are given longer timetables for implementing many important provisions and
commitments precisely in order to allow them to protect nascent industries if they want
to.