I just checked more chars and i have 2 who might have lost a bank item (no idea what) and i am pretty sure (not 100% though, since i might have manually deleted it for space reasons, but i also had lots of space in bank) i lost a yellow wardstone on one char i think i did not even log after the merge (and if, just did a few quests). The wardstone was in the bank and seems lost, but i had a cell door key in inventory which i kept. I am not checking for quest items here, though.
What is the source of your detailed info (more detailed than any official one so far!) in post 111 ?