Birks Grange is lovely brand new accommodation. I wouldn't worry too much about the stuff on social media, particularly if these people are in her block but not in her corridor/flat - the party animals are likely to be the loudest ones on social media anyway and perhaps others are just joining in to try and fit in?
IMO you get party people in pretty much any of Exeter's halls (perhaps a little more so in the more modern halls which have a reputation for being 'posh', but by no means isolated to there), but equally there are plenty of students like your DD. I know it feels super important to most first years to be friends with the people they live with, and to be honest quite a lot of going out and drinking in flatmate groups seems to happen in Freshers Week in the rush to establish friendships. But for the majority it settles down over the first term and people gradually start to find their 'real' friends through their course, sports, hobbies, societies etc., and so who you live with becomes less important (so long as they are reasonably considerate and don't ruin other people's experience with their partying of course!). Which when you think about it makes more sense that your friends would come from the people you have a real connection with rather than the fairly random allocation of the uni computer! So she needs to not panic if these people turn out not to be 'her' people if you see what I mean, her people are out there, maybe just not in her flat!
And be reassured that if she is really unlucky and has drawn the truly unreasonably drunken/loud/messy arseholes (there are a few) rather than the more normal 'go a bit mad in freshers then settle down' flatmates, there's usually quite a bit of accommodation movement over the first term with dropouts and/or people not liking their flats and wanting to move somewhere cheaper/closer/catered/self catered etc. so she will probably have a chance to move. She may be able to find a party animal who's been allocated a quieter flat to swap with if that is an issue - the uni is usually quite supportive. But I'm sure she'll be fine anyway! Best of luck to her!