As for the rest, the original purchase agreement was ambiguous on how refunds would be calculated, but there were representations by HashFast that BTC payments would receive an equal amount of BTC in refund. And that's generally the way refunds are understood. This group buy paid HashFast entirely in BTC.
Given they were paid for in BTC, then that definitely suggests a BTC refund. That also aligns with what others were saying.
Perhaps with the Mt Gox issues today, BTC might be cheap to come by this week.