Good luck to them.

However, "1-2 million BTC" is an estimate for what MtGOX owes its clients, not of MtGOX's assets. 

MtGOX's assets are the real BTC it has in its orporate wallets (and whose keys are not lost  ) and the money it has in its corporate bank accounts. From those assets one must subtract that 1-2 million BTC of account balances (ie. ~1 billion dollars), in order to get the company's net worth.

Mark's personal wallets and bank accounts are not MtGOX assets.  To get hold of them, I suppose one must convince Mark to invest in the New MtGOX, or sue him; and only the creditors (including his clients) can do the latter.
 
So, MtGOX's net worth may be anywhere between plus a few million dollars and minus a billion dollars or more, with several lawsuits for dessert.

Moreover, who knows how many of those "1 million accounts" are active and/or have positive balance.  My guess is less than 10,000.

If that project succeeds, it may go down in history as the, ahem, weirdest company takeover ever...