Timing of the opening definitely seems like a big deal, but I'm not sure it makes that much of a difference. When you first open you shouldn't be in desperate need of anything (except maybe attention), so I'd say don't rush things in order to make a particular season.
As far as waste goes, Jean-Pierre Wybauw's books discuss re-processing leftovers and seconds. Definitely worth a look.
The usual factors in small business failure all apply to chocolate...poor location, lukewarm marketing, unrealistic sales forecasts, poor money management... I found very little specific info on artisanal chocolate as a business niche. Following news articles on the subject can reveal some good figures and provide insight, though. Subscribing to the NASFT newsletter isn't a bad idea.
Issues specific to chocolate are its seasonal nature (you sell virtually nothing all summer, and have to deal with the difficulty in working with/storing/shipping product) and inventory control. Good artisanal chocolates will have a shelf life measured in weeks. You need to be sure A) customers are always getting fresh product, B) you always have product on hand to sell, and C) you aren't spending all your time in production.