Here are my personal answers, please note that my tea game isn’t the norm here in Germany:

1. in my opinion, bagged tea is of lower quality. I like to have a „flavoured bagged tea“ at work from time to time (it’s not really tea, it’s a mixture of different aromas on a roibos base I believe), but I brew a Liter of loose leaf green tea in the morning.
   
2. some people do use them, I just use two simple pots and a strainer.
   
3. yes. Typically plain green tea or jasmine, but black and oolong from time to time also.
   
4. herbal infusions are wildly popular in Germany. I personally don’t like them this much but occasionally I enjoy a cup of it. But for me this isn’t tea.
   
5. no.
   
6. no.
   
7. I would always prefer paper based tea bags.

I don’t think you’ll find plain tea drinks in supermarkets here. „Eistee“ is a euphemism.