http://www.prowrestlingsheet.com/details-ronda-rousey-not-leaving-wwe/#.XEn9IVX7SUl
This seems to suggest that she'd be taking more of a hiatus as opposed to being completely done. The timeline here, her asking for time off around Survivor Series and them agreeing to write her off at Mania, would put them into the clear in terms of Fox. At least, it would suggest that WWE weren't outright working them.
Apparently Ric Flair said a few months back that Rousey was done after Mania but he could have misinterpreted that info and passed it on to Dave or whatever. I would certainly be hugely surprised if Mania was the last time we see her working a match.