Ranked 3v3 Flex?

Hey guys, since Riot support won't respond to my tweets... What does playing ranked 3v3 actually do?

I was able to have silver ranking on 3v3s for season 6, will my mmr stay at silver for 3v3s?

Will my season 6 3v3 team mmr be affected or have anything to do with the whole new 3v3 flex system? Does my season 6 3v3 team mmr even stay, or will it be completely wiped?

Does my season 6 mmr have anything to do with my 3v3 mmr? Does this allow you to play with people 2+ tiers above or below you during placements?

When I finish my 3v3 flex placements, does it change my original mmr or change how I do in season 7 placements? Thank you in advanced.