Hello sting204 and welcome to CheeseForum.org! Good questions and while I'm not a guru I'll try to answer the best I can:
1) Use store bought skim cow's milk, somewhat. No problem with soft cheeses where you will get a low fat version of Neufchatel etc. But for hard, pressed cheeses it is more difficult as the fat in the milk is critcal in forming the texture and body of the cheese, especially ripened cheese like Camenbert. This is the reason most non-fresh cheese making recipes use whole milk, and some even add cream! However some Italian cheeses such as parmesan can be made with skim milk.
2) I haven't made cheddar but my understanding is just the starter culture is the only one.
3) For brie and blue cheeses, the inoculum is added either with the starter or after removal of whey depending on the recipe or inoculum.
From my experience, my suggestion is to start with simpler fresh cheese and work up to harder pressed and eventually blue and camenbert. This is because i) fresh cheeses need little special cheese press type equipment to get going and ii) you don't have the "Cheese Cave" aging control issues of temperature and humidity to deal with. For example, I found the
Neuchatel recipe posted here quite easy. In my opinion, making pressed - hard cheese is more complicated and sensitive than making wine or beer as the ripening/maturing process for non-fresh cheeses is out in the open and subject to temperature & humidity issues sometimes resulting in wrong bacteria infection, dry cracking, or airborne mold.
Hope this helps and also that reg and or others have opinions. Good luck, we'd love to hear/see what you choose and how it works out!
