If it is profitable to mine the BCC now, will the miner mine it and then dump it to drive down the price?
Miners don't want to drive down the price of anything they mine - they want the price to rise. So they'll sell slowly, feeding the coins into the market.
Mining at scale takes quite a large investment now. The overhead is tremendous. So, inherently, miners are bullish long term on the coins they mine, so they are selling as little as possible -- just enough to cover expenses and keep their investments growing. So, if we see miners defect to Bitcoin Cash, it's because they are long term bullish.
Or because they are Bitmain and they are manipulating perception!
how do you know what miners do with the coins they get? there is no way of knowing that. they may as well sell it as soon as they get the reward or never sell it at all.
and miners switching to anything else only shows that they want more profit and just because mining that new thing is profitable for them at that point. that is how all the altcoin miners have ever acted so far. they keep switching from coin to coin and dump them as soon as possible.