Can't say for sure if Plustoken dump has any bearing at all. The remaining Mt Gox Bitcoin funds might be more dangerous if dumped. The markets are weak. But it will end for sure. So, it is best to prepare for the bottom.
I do not think so that the entire tokens are dumped into the market as of now, as per the articles it was more than $100 million worth and if that happens the price of ETH will go down below $50 without a doubt, but we have not seen that kind of sell off in the market even though the articles were flooding with all the speculations, lets see how the market will go as the amount of tokens they are holding is really huge and it will have an impact on the market.