Unless the rebel group have many billions of Dollars they will only be able to artificially support BCC/BCH for so long. Just dont sell BCC/BCH to them too low. Sell it higher to drain their funds quicker and dont place buy orders.
I am pretty sure they have billions of dollars allready. And as you say, they will maintain the price for a long time. I can only see the logic in this action if they actually think the price will rise, and the question is if they have dollars to do so?
I really dont understand why they will put all their asics to mine this cash coin.
It's going to be pretty clear that it's more profitable to mine BTC, and then miners will move away from btccash.
No matter how they come out of this fork, they will be richer
Until the next difficulty change for Bitcoin Cash that is then things will get crazy, it might take a while, it might take years but that little blip will initiate the sequence.