I trade CFD's through IG markets and, although I'm NOT short FGE, I would expect a maximum return ie. another .915 if worst comes to worst. Trading CFD's is no different to ordinary shares and you are entitled to whatever price the market is paying, even if that is 0. I would be surprised if my (or any) CFD provider had already closed any position.
The only issue for a trader who had a short position in this situation would be the margin involved. Before the halt IG had a margin of 25% on FGE, which is a hefty chunk if you trade at 50%, but considering the likely outcome you could bump that up to 75% in the meantime without much concern.
Also a guaranteed stop can only be added when you place the original order, once the order is open only a stop loss can be added and that wouldn't help you here.
FGE Price at posting:
91.5¢ Sentiment: None Disclosure: Not Held