@John Lewus, it's obvious you have been paying attention to your daughter and are trying to do everything you can to help her. I can only imagine.
Yeah, sticking with CBD is probably the safest. I know I wouldn't want to get my kid high (well, actually, I did lend my Firefly to her, but she's 35). However, I don't think I'd be comfortable with the mask, due to the lack of oxygen. In fact, I'd think that would be very dangerous.
I do have an idea (though I've been trying out my new hydrabomb, so take it for what it's worth). When I was young (20-ish) I occasionally, while camping, sat under a blanket with friends and smoked joints. We got waaaayyyy stoned well before anybody was gasping for air.
Perhaps sitting under a blanket with Herbie with her, while it vaporizes a high-CBD/low-THC strain or oil into the air (just remove the whip, and turn on the fan) would work. My only concern would be that her seizure may not be alleviated quickly enough, as I'd imagine injected Valium is pretty quick-acting.
Remember though, I'm just a guy posting on a forum. So, I'm just throwing stuff at the wall, and not making any recommendations. And I'm medicated.
Oh, one other thing. If I was dealing with this, I'd definitely discuss it with a good attorney, whose advice you trust, in advance. It'd be really fucked to hear that your daughter had been taken from your care!
In the end, I'm sure you'll research the topic adequately, and make your own informed decision. Best wishes.
Now, back to testing the Hydrabomb/Herbalizer combo.