1. Yes
2. Yes, and scouting data is provided in the client so make sure everyone has some back up picks!
3. Players roles are not shown
4. It's not double elimination but you are guaranteed at least 2 games so if you lose in the first round you get a consolation match for slightly better rewards. Lose in the second+ round it's over.
5. You can play both days
6. Unfortunately no.

TeeFellaLava

Okay thanks for the answers. I had additional question about Elo. If all my team is silver, could we end up playing high Elo like plat, diamond, etc? Or will they be roughly out Elo?

Roughly your elo. Maybe a little higher or lower depending on how many teams enter but our goal is to keep the elos fairly close

HeyItsChase

I have a question. Hopefully here is a good spot for an answer.

One buddy is diamond one buddy is bronze can they play together?

You can! Be aware though that the matchmaking will heavy favor the Diamond player (it's not an average) so your bronze buddy will be out of their element.