PvP Brackets on Icecrown.

Hi, i'm very confused. :D I didn't played WoW on this server for years, i came back some weeks ago and today i tried to join Battlegrounds with a level 68 character on the Icecrown realm and now i have multiple questions:

1. I see that just on Icecrown there is 12.000+ players online and i think there is even cross server PvP, but then how its possible that i'm waiting for 2 hours for one Battleground and the game keeps saying that the wait time is 16 minutes without any change?
2. What is even more confusing for me than that is that there was a level 70 guy in my team. How? I thought that Battlegrounds are for 0-9, so for example from 60-69, how can a level 70 join to the 69 BG?
3. Is 10-19,20-29 etc Battlegrounds even exist on this server?
4. Do you even get experience for BG's here, or not at all?
5. Btw there was "not enough players" so it ended pretty fast, under 7 minutes, because i got the achievement. Its not a question, but it looks very boring to wait 2 hours for that.
6. I read multiple topics about ilevel brackets on level 80 while i tried to search for this, is that on every level or only on 80? Because if that's going on on every level and its a "hidden" stat then i'm going to be just even more confused about all of this. Looks like a mess to me. I'm really not sure that i want to invest so much time into this game to figure these things out by myself.

So... Thanks for any answers.

1. Because nobody plays BGs at 60-69 bracket. Active brackets are 10-19 and 70-79.
2. Depending on how many people there were/are currently queing BG sometimes they pop as a Skirmish where you do PvP with no BG objectives in a BG map. That could explain why you fought a lvl 70. It also lasts infinitely.
3. 10-19 exists, others pop VERY rarely.
4. Wouldn't know, I don't do BGs at low levels when I'm not twinking much like everyone else on the server.
5. Blame the playerbase for not wanting to get dicked by twinks on every bracket, so they just don't que at all.
6. ilvl brackets are active only on lvl 80. They are split in 2 ways. If you have gear that is at current Frostmourne's gear level you get put into their bracket. If you have even 1 piece of gear from Ulduar or ToC or any dungeon like FoS/PoS/HoR you get put into higher tier bracket where people like you are, including BiS players.