Reb Eliezer, you quoted the Mishna Brurah. However, this is actually a great machlokes haposkim, with MANY poskim clearly ruling that one is allowed to ask deceased tzadikim (their neshamos) to intercede on their behalf.
For example:
???? ????, ??? ????, ??? ?????, ???? ????, ??? ?????, ???? ????, ???? ?????, ?????, ???? ????
These poskim explain clearly why this is not ???? ?? ?????.
The poskim who don’t allow it have many ????? ??”? to answer, where it clearly mentions ????? ???????? (and Kalev) who went to ????? and spoke to the ?? with various requests.
???? ??, ?. ?????? ???? ?. ????? ??,?. ????? ??, ?. ???? ????
And of course the Zohar.
Everyone should follow their minhag and their rov.