Releasing at Christmas is important for them. Their selling strategy is based on that period. The date could have been set sooner actually, meaning they're having a comfortable margin. At the moment, the production progress is a success since YSnet managed to officialize the teaser and that's kind of an achievement according Cédric.
It's too late to predict something wrong to happen but personally I really believe we'll get Shenmue III at the right date. Infact, it will depend mainly on the ability of Epic, Sony and YsNet to work together. I think Yu has experienced more complex situations than that.