But the delist occurred after conservatorship was implemented.
Nope. Conservatorshiop was imposed on September 26, 2008. FHFA didn't get the shares delisted until June 16, 2010.
RELIST, Helps the RECAP, and then ensures the RELEASE.
The real order was conservatorship, delist, and then decap (via the NWS). So to reverse it, it's recap, then relist, then release. If the recap involves dilution (nearly certain, in my opinion), a reverse split might be necessary before the shares could be relisted.