Interesting analysis. In retrospect, SCOTUS leaves the door open to legal challenges to how the conservatorship was run if this doesn't get resolved in not too distant future.
So I agree and think a settlement is possible, with SPS declared paid and perhaps the treasury settling for 20% or so of warrants in the GSE's.....and then purchasing them.
With this reduced but now actual interest coupled with a reduced capital requirement that you refer to, that gives Treasury incentive to also receive a contingency fee to further cover any future housing downturns that might affect GSE liquidity.
So treasury winds up with 20% of the GSE's and their profits, plus contingency fees going forward. And a stabilized GSE situation.