Sherrod Brown is the ranking Democrat in Senate Banking, so he is in line to become chair if the Dems win the Senate. That's huge, he's one of our biggest allies. It would also castrate Sen. Shelby, current chair and man behind the "gov can't sell its shares without congress" rider in the omnibus spending bill, who is our second or third biggest enemy.
In the House, Maxine Waters is the ranking dem on House Financial Services. If by some miracle the dems took the house, she'd be chair. She too is one of the GSEs biggest allies.
Even with only Senate Banking under control, this essentially eliminates the possibility of legislation winding down the GSEs. The concern at that point, as far as the shareholders go, would be that they go the opposite direction and effectively nationalize. That would be very hard to do given the size of the balance sheets and the absolute uprising there would be from congressional republicans, but if they were able to pull it off, I think they'd basically have to buy out the prefs. The commons don't have nearly as bright a future in that scenario.
However, assuming Hillary wins, it's very likely that her administration (Treasury and her economic staff) would be very anti-GSE. Larry Summers, Gene Sperling, etc.
Don't underestimate how much political resistance there will be to restoring them even if the dems are in charge. The system really was pretty screwed up, and few people want to see the kind of corruption that was going on come back. With a government guarantee as the basis for your business model comes the need to PROTECT that guarantee, and the only way to do that is lobbying and playing politics. No one in congress wants F&F to start that up again.