How Many btc could they stil have to dump



Only the first 10,000 of the 160,000 stuck transactions went through. There are many people who've been trying to sell BTC for over 1 day now, but have had their coins stuck in mempool:

As the remaining 150,000 stuck transactions get processed, we could see continued dumping.
I think we'll see BTC fall to a low between $3,000 to $4,500 over the next few weeks, before the BCH FOMO wears off for this wave and we get a significant rebound.