In conservatorship shareholders have almost no rights at all, commons and JPS alike. The "fate" of FnF is solely determined by agreements between FHFA/Calabria and treasury/Yellen.
Preferreds are selling at a premium vs commons, a premium many feel is not justified.
LOL. Is this your conclusion because commons trade around $2 while most JPS trade around $6? I agree that the number 6 is greater than the number 2.
One could argue that JPS trade at 20% of real (par) value ($25), while commons trade at 1% of real value - IF you assume (like many here) that the commons' real value is $200. However, in more realistic calculations the commons (after warrants execution and cap raise) will have a value of just $5. Based on that, they trade at 40% - which is a premium to the 22% of the JPS. (That's why I think with JPS you get more bang for the buck.)
Preferreds [are] "hybrid" between bonds and stocks
Correct. That's why comparing JPS to commons is like comparing apples to bananas.