YFII is a fork from YFI just like some forks of bitcoin. It has been listed also in many platforms that YFI is listed and trading volume and price seems to have dropped in the past few days. I think huobi are monitoring closely the defi and decision to list YFI must have been because they also want traffic going to defi to also come to their trading platform and choosing YFI is not a bad idea because it seem it is one of the most decent defi project right now