FWIW, today didn't see the drain. Still at 60+% as I write. Didn't uninstall or clear cache or data on FB. Whatever they did after yesterday's issues seems to have fixed the problem. Android System and Cell Standby are today's biggest hitters.
I've been using Friendly lately and it has been working well for me (and no battery drain!) and it improves with each update. However, I will admit I'm not an avid Facebook user, so your mileage may vary.
I quit using the Facebook and Facebook messenger app and switched to Swipe. I get noticably better battery life since the switch. I switched before the server issue they announced Wednesday.