In principle the options are :
1. Move to another exchange,
2. Close down - and distribute funds approximately in ratio to what market prices were just before the announcement.
Problem with #2 is it's going to be hard to have any sort of rational discussion over how much should go to mining and selling as everyone with an opinion likely has a lot of one and not much of the other so isn't unbiased. Market prices is the only way to go - as those represent the prices people were happy to hold at (noone was trying hard to buy more of whichever they held or was desperate to sell into bids - or they'd have done so).
If problems arise with recovering investments then loss/delay from that MUST go to SELLING not MINING as SELLING were always getting the benefit from investment.
A few things seem pretty obvious immediately:
1. No new investments should be made.
2. Where investments can be cashed out they should be - so there's no further changes in NAV/U.
3. Debatably I should withdraw all funds to a BTC wallet under my control and only return them when distribution is to occur.
4. Trading will be disabled on PURCHASE - I won't sell more shares now obviously and also I can't redeem them until I'm sure all investments are safe and will be recoverable. It would be bad form if I allowed sale back of PURCHASE then found we couldn't get one investment back and so those who had sold back had received more than their fair share.
5. Similar to 4 I won't be redeeming pairs of MINING+SELLING.
This isn't a situation explicitly covered in the contract - but rest assured I'll resolve it in the fairest way I can.
Personally I'd favour option 1, since DMS was a fun fund to mess around with. But if that's not an option, then the plan you laid out for termination looks fine to me.