1.. Buttermilk can be purchased from Tesco in the cream section above the milk it is in yellow and blue cartons and is just soured milk done by culturing you can use it to culture other milk by adding some to a pint and leaving it overnight in a warm kitchen and the next day you have buttermilk and this can go on ad infinitum.
2..I use an old upright freezer switched off. it is easy to maintain a temp of 45F and the RH is got by using a plastic box or dome to keep the moisture in the cheese.
3...cellophane can be bought in an art material shop or use greaseproof paper. Only thing is do not use clingfilm as it doesn;t allow the cheese to breathe..
I've always wrapped cheese in greaseproof paper, its much better than encasing it in plastic. I haven't tried cellophane though and I've got plenty of that, so I'll give it a go.
Cellophane is semi-permiable, but clingfilm isn't. It's why cellophane went out of fasion as a food wrap in supermarkets: it may keep the food in better shape because the food doesn't "sweat" and it gets some gas exchange, but it looses water and, therefore, weight.
The WI (I'm in it!) questioned the excessive use of plastic packaging in supermarkets a while back and were told that an EU directive insisted on the style of packaging we have for fresh and cooked meats and fish because of cross contamination dangers.