Generally baking powder will last for six months to one year.
If properly stored, chocolate can last up to one year.
As long as the chocolate is not exposed to extremes of temperature, it should last indefinitely. M&Ms travel better than a chocolate bar would.
None specifically. The kind of chocolate used for baking should be high in cocoa solids - percentages are usually listed on both baking and eating chocolate. As long as you buy an eating chocolate high in cocoa solids (65% or higher), it will be fine to bake with (assuming no weird "fondant centres" or "caramel chunks" etc...). I think 'baking chocolate' is primarily sold to people who do not bake often, so do not know what to look for when choosing a chocolate variety with which to bake.
FOREVER but as long as you don't eat it first
2 to 3 days normally.
In general, cheesecake of any description is baked if it contains eggs. I have made chocolate cheesecake without any eggs and it only required refrigeration. The use of chocolate is not relevant, I found, to whether baking was required. You do realize, I hope, that whether you bake your cheesecake or not, it will not last long.
Chocolate cake will be good for approximately one week when refrigerated.
If stored properly (cool, dry place), it can last for about a week.
Once a can is opened, fresh baking powder should be good for 3 to 6 months.