1) As wheel says, to graveyard from anywhere goes to bottom of library instead. The druid sends to graveyard but doesn't care if it actually arrives.
2) Time stretch goes on stack, curse of echoes sees this and triggers, curse of echos resolves, opponents place copies on top of stack, copy resolves, original resolves.
Partner gains life, does it trigger?
I play Zealous Conscripts to take opponents creature
In my second main phase I use Tamiyo to tap the stolen creature
End turn, creature goes back to opponent
Does it untap?
-3: opponents life becomes 10
Can the life loss involved in setting total to 10 be redirected to opponents planeswalker?
2) Time stretch goes on stack, curse of echoes sees this and triggers, curse of echos resolves, opponents place copies on top of stack, copy resolves, original resolves.