As this answer to another question points out, the MM errata replaces resistance/immunity to "non-magical weapons" with resistance/immunity to "non-magical attacks".
Does this mean that a werewolf can't be burnt or drowned?
As this answer to another question points out, the MM errata replaces resistance/immunity to "non-magical weapons" with resistance/immunity to "non-magical attacks".
Does this mean that a werewolf can't be burnt or drowned?
Werewolves aren't immune to all non-magical attacks, they are immune to "slashing, piercing, and bludgeoning damage from non-magical attacks" (emphasis mine).
Being burned at the stake would deal fire damage, and fire is still quite effective. Suffocation does not rely on dealing HP damage to kill in the first place.