As to Mary suffering for the sins of man, all the baptized are offered the same opportunity because we are baptized into Christ. There is nothing remarkable there. It’s all over Paul.
And so where do you see the Holy Spirit saying Paul suffered all the consequences of sin and we are saved through his merits? Even if said in a certain technical way, a recurrent problem in Mariology is that it expects the laity to understand such, thus the language of Scripture is reticent in praise of men and very sober in its assessment of them, while exalting God repeatedly and as unique. Thus even the Trinity is not explicitly spelled out.