You dont use anything sweet
Yes. Most of the time, the terms "bittersweet" and "semi-sweet" are used synonymously. Technically, bittersweet does have a higher cacao percentage, but even then the difference shouldn't do much to change a recipe.
Semisweet chocolate has sugar in, unsweetened has no sugar.
Yes no difference.
about 16
When you put the chips in, add sugar.
That is usually done by adding sugar, milk, eggs, and other sweetners.
Yes.
Yes, however the texture and taste will be a little different. Chocolate baking squares are usually unsweetened or a very dark chocolate, while Chocolate Chips are usually semi-sweet or milk chocolate.
A good substitute for German sweet chocolate in baking recipes is a combination of semi-sweet chocolate and sugar. You can use 1 ounce of semi-sweet chocolate and 1 tablespoon of sugar for every ounce of German sweet chocolate called for in the recipe.
unsweetened applesauce
It will be down to personel taste. Try it and report back.
If you do, just be aware that it will not be as sweet and the final result might come out a bit more bitter. Other than that, you usually can substitute them in.