mining is the biggest driver of many coins. they gotta sell to pay the bills but also anything mineable instantly guarantees interest and volume.
if it goes pos that might wipe out a vast amount of volume, but it also wipes out the need to sell. i don't really know what might happen to be honest.
Yea, hard to tell, especially for long term. Short term there might be a pump, if nothing breaks. There is a fairly high probability that something will break, imo