don't get me wrong your ideas are great.
But you're making a huge mistake here.
look, i'll try to explain.
Tier1 for example:
Swift, u8 , shotgun, lux, talrand wargasm
Swift is the best player, then comes u8, then lux, and so on....
now the already best player gets to choose first and takes the best player from tier2.
do you think that's fair?
The worst player from tier1 should be allowed to choose first which player he takes from tier2.
That's the only way you can get fair teams to begin with.
otherwise you have the best from tier1 + the best from tier2....