Playing MTG: Duskmourns Archenemy In my particular Archenemy playthrough, we actually had a fourth player against the villain (it wouldnt have been nice to leave a friend out) and I must say I dont think that gave us an advantage at all
No, you cannot block fight
You also get quite a few ways to ensure that you can sneak some bonus triggers and poison counters in through simple spells like Prologue to Phyresis, which just gives each opponent a poison counter, and Blighted Agent, an unblockable creature with infect.
Mind Over Matter, meanwhile, can draw and discard cards in a never-ending loop to mill out right away
Proxy cards are not allowed in official tournaments and some causal players frown upon them as well
That includes during your opponent's turn, or in response to game actions, like your opponent declaring a blocker, or the turn moving from one phase to another