From the people I know who have/are building the actual sites there I have been told most of their staff is their own people shipped from overseas. It's going to take a few more years of training US staff and getting fresh graduates out of the local Universities before they are ready to make significant strides in US talent. This is a significant investment for them and I'm glad it's working out. They are picking up where Intel has failed in the US which is a sad but true statement.
Granted this is only a minor source from people with limited inside access once the construction is mostly done. Just thought I would share it.
