That only works if the foundry is convinced that you are worthy of credit. Normally this is not the case for start-ups and SMEs in this price category. For them it is cash in advance or no tape-out. Yes, I know what I'm talking about, it's hard to deal directly with companies like GF or TSMC if your are only a small customer.

I doubt that KnC or OrSOC is seen as a big customer for this project, because they probably will not order more than 50 wafers in the first year (which would be already about 3 PH). 1000 wafers a year would be a big customer. Why should a foundry take any risk for a bitcoin mining ASIC?
So I think they most likely have to pay the complete $1.5M to $2M in advance of the tape-out. And because they said tape-out done "some time ago", they probably paid it also some time ago.

From the commercial point of view I see no reason why KnC should not be able to produce a fully designed 28nm ASIC. They collected enough money by pre-orders to pay the complete 3rd party NREs in advance. But it should be clear, that if they are on track as they claimed, a great deal of the pre-order money isn't in their hands any more.