Setting up a "facility", helping Saudis buy Chinese missiles, and having troops in Saudi Arabia have nothing to do with a nuclear umbrella.
Definition of "nuclear umbrella" according to Wikipedia:
"Nuclear umbrella refers to a guarantee by a nuclear weapons state to defend a non-nuclear allied state."
Source:
Nuclear umbrella - Wikipedia, the free encyclopedia
Are you telling me Pakistan will use its nuclear weapons to protect Saudi Arabia if it's attacked by a foreign power, including Iran and/or Israel?
And didn't Pakistan say that its nuclear weapons are only India-specific? And now you are telling me Pakistan is going to provide a nuclear umbrella to GCC? This big news, isn't it. Yet I don't see it reported anywhere. Please cite a source.
And, yes, Saudi Arabia is seriously thinking of purchasing nuclear weapons, to mainly offset Iran:
Saudi Arabia Considers Nuclear Weapons to Offset Iran - WSJ
And where are the Saudis going to get the technology? From Pakistan, of course. One thing Pakistan knows how to do is play the nuclear game. And rumors have been floating for years that there's secret deal between Pakistan and Saudi Arabia to for nuclear technology. Saudis, of course, deny them.
Is Saudi Arabia seeking nuclear weapons from Pakistan? - CNN.com
As for a document known as the NPT, we all know that it isn't worth the paper its written on.