Just because WAMU wrote $100's of billions in loans etc doesn't mean that they owned $100's of billions in principle and interest payments. This is why I do not believe in the $100B+ estimates. That said, a lot of WAMU's property IMO resides with the FDIC-R/C but since they are a semi government body, full transparency is lacking.
Read the POR, there are several (3 in total??) provisions where Assets of WMB could be retained by the FDIC for specified reasons. One example of such is where Receivership Assets that backed certain securities could be withheld from sale to JPM, thus allowing the FDIC to settle outstanding Receivership claims. This could be in reference to the WMB Notes for which the FDIC is responsible. In addition the P&AA intimated that JPM "DID NOT" purchase all of WMB.
Safe Harbor is designed to protect qualified assets and their investors from, the Debtors (WMI), Bankruptcy Creditors (AAOC), FDIC Receiverships (FDIC-C or R) and Purchasing Entities (JPM). Based on this, the only outstanding issue is the FDIC's WMB Receivership which still has billions in debt owed to DB and the WMB Noteholders.
IMO, this is the last impediment preventing the release of Safe Harbored assets to our Markers.