>ths ONLY thing you find chazal advocating is asking for the niftar to daven on your behalf.
Avira, when I mentioned the poskim I clearly wrote “to intercede on their behalf” – because that is what most of the poskim whom I mentioned discuss.
However, when I mentioned chazal, I intentionally wrote “various requests” because if you go through those gemaras you’ll see that they did NOT only advocate for the niftar to daven on your behalf, rather they came to ask various other things from the dead (either seeking information (such as with Abaye in Brachos), or for the niftar to move his body (such as with Moshe and Yosef in סוטה יג), or to ask questions in learning, etc.)
The Rama clearly rules (יו”ד סי’ קעט סי”ד) that one is allowed to ask the neshama of a deceased person to swear that it will come to him and answer his questions.
This is what I meant by “various requests,” and I stand by what I wrote.