According to new rules laid out by the CFP committee, if a team in the playoffs has to forfeit the other team moves forward and can, in fact, be declared national champion if the game can't be rescheduled by the January 14th makeup date. If both teams can't play the national championship is vacated this season and nobody gets the title.
I'm not a fan of this at all and I doubt anybody being "awarded" the championship in this way would consider it anything other than a huge asterisk.
I find it ridiculous they would allow a 4 day window for rescheduling and that's it. Both teams would obviously rather play the game, even with a longer delay.