It's also possible that FHFA directs FnF to offer a voluntary conversion at a specified ratio, as with Citi. This doesn't require any voting by pref shareholders.
Sure, but that's a tautology. Without any knowledge of what law a conversion would break, how can any lawsuit be anticipated?
This "ALL" certainly won't include current common shareholders because they won't have a say. It will be the pref shareholders negotiating with Calabria. Possible exceptions to the above are Bill Ackman and CapWealth, who between them own 20% of the commons but are still more heavily weighted to the prefs (meaning that a generous enough conversion makes them enough money to eat a loss on the commons).