If the dreamer is dreaming, and all the projections are destroyed BUT there are no (or maybe just not enough) hero ongoing cards, does the dreamer awake anyway?
In other words is destroying the ongoing effects part of the COST of waking the dreamer, or a side effect?
It's just a side effect, so she'll destroy whatever she can and then flip.
If you don't see the words "If you do", you generally don't have to worry about being instructed to do the impossible. There are a few exceptions but they're mostly due to outdated wording, and of course the Dreamer is part of the latest expansion (until next year), so it's pretty safe to say her wording is right (except on the oversize card).