Margo will be fighting alongside her fellow magicians, bottling away her emotions to do badass battle magic for the occasion. She'll stick it out as long as Eliot does and be beyond spent, both physically but especially emotionally, by the time it's all said and done.
Teddy will also be out there, his Auror instincts kicking in immediately.
Posy and Fleur will not be out there, the latter especially miffed about it because she's pretty good with her dueling and defensive magic and hates that her husband is out there without her. Posy will hang out around Annie and the kids, while Fleur will probably wring her hands and fret.