I hope things go well at the meeting.
Since you're concerned about how talking about the problems will just make it worse, can you cut her off at the pass? Explain in the meeting that you anticipate, based on past behaviors, that she will in effect make you pay for bringing up the problems and what do the professionals suggest in terms of dealing with the fall out. Is there a crisis team available? Should you have her transported to hospital for evaluation? Etc. I'd just bring it up in a matter of fact way and ask them for help.
Sorry you're dreading the meeting - that's always a lousy place to be. I hope they are able to come up with some good ideas for you and hopefully your daughter will be more receptive and rein in her backlash. Good luck and let us know how it goes.
