Great observations:)
About point 5, unfortunately it's not just the 8th graders...
It's funny and kind of sad that heavy metal is considered a favorite among most of the intelligent bulgarian teenagers, but it all has to do with conformity and lack of information in this country. If you're a teenager forming your identity and relationship with the world, no matter how smart you are. you feel the need to belong, so even in the unlikely case that you've somehow heard more musically subtle and lyrically intelligent music (indie rock, new wave, punk (70's), post-punk (80's),  etc...) you have no incentive to choose that music over heavy metal, simply because in Bulgaria you will be the only one listening to it. I think that intelligent music is unpopular in this country because up to '89 there was very little outside influence here plus the english language skills of most people here are seldom at the necessary level to appreciate the more complex lyrical themes (for example how many Bulgarian fans of Morrissey are there? I've never a single one, except BG people who have lived abroad for some time.) And he's been massively popular in the rest of Europe since the The Smiths years).