Of course they are. They are in the equity portion of the balance sheet. I don't see how anyone could argue that they aren't equity.
One good way to tell who owns a company is look at the BS. If they are listed as Equity, they are owners.
"Ownership" is not well defined here. Some common shareholders like to say that "common shareholders own the company!", to the exclusion of preferred shareholders, but that argument hinges on voting rights. At the moment, common shareholders have no voting rights at all because HERA says that FHFA succeeds to those rights as conservator. Which in turn means that current common shareholders have no ownership of FnF at all.
I believe the Seniors are also not convertible.
Treasury does not have the right to convert the seniors to commons without FnF's consent, but nothing is stopping FHFA (as conservator) and Treasury from agreeing to a senior-to-common conversion.
What I do believe is that at the end, the gov will take a cut in the RV for reasons previously stated.
Treasury's senior pref liquidation preference right now is $173B for Fannie and $104B for Freddie. The companies would most likely be worth less than that on the open market.
Since FnF will have to raise capital to get out of conservatorship any time in the next 6 years, and since new investors will want some of the equity of the companies in return for their capital, Treasury will have to take a haircut on the liquidation preference of the seniors.