How are Commonwealth countries affected?
It has the same effect as everyone else. Good news is that the English speaking requirements are practically a given.
In the future I can see free trade deals with the Anglosphere and Commonwealth countries include more preferential and reciprocal visa arrangements as part of the deal.
Have the same point system in Canada which Trump supposedly wants to copy. I know as im from there and have family members who work for the govt. You have to submit everything from BLOOD ( yup. ) assets, education, properties to show you will not be a burden to the system.
Commonwealth countries are positively affected. There will be more immigrants from the subcontinent. Most would be Indian Hindus, Christians and Sikhs but there will be Pakistanis muslims too, hopefully the educated non radical ones