Looks like if I will be filing tax for 2019(which I will be) then I should not use non-filer.
I did call IRS for this query and surprisingly IRS did receive my call but then IRS representative too got confused with this question of mine.
I am thinking of calling them again.
My wife should have got SSN in Jan 2020 but Due to their irresponsibility it never came and I have to deal with this consequence.