Regenerate / Wither (Magic the Gathering)?

Question

Regenerate (501.5a) means “The next time [permanent] would be destroyed this turn, instead remove all damage from it and tap it. If it’s an attacking or blocking creature, remove it from combat.”

My friend attacks with a 1/1 Wither creature and I block with a 1/1 creature. I play a Regenerate instant on my creature.

QUESTION:

1) Will my creature survive because Regenerate "removes all damage from the target creature and removes the creature from combat"; ie the Wither damage (-1/-1 counters) will be removed? (IMO yes my creature would survive)

2) Will his creature survive since my blocking creature was "removed from combat". (IMO yes his creature would survive)

My friends and I are aware that Regenerate does not work on a creature that has enough -1/-1 counters on it to lower it's toughness to zero. But since Wither is damage in the form of -1/-1 counters, I believe that Regenerate will "remove all damage from target creature" and mine will survive.

Answer 1

Your creature will die. There is a difference between a creature having lethal damage (damage equal to or greater than it's toughness), and having 0 toughness. This is explained further in the State Based Effects, the relevant two are below.

1. A creature which has lethal damage is destroyed. Regeneration can replace this effect.

2. A creature that has a toughness of 0 or less is "put into it's owner's graveyard".

Since -1/-1 counters cause toughness to go to 0, it's put into the graveyard, not destroyed. And since regeneration only affects destruction, it does nothing to putting in graveyard.

Answer 2

In essence your creature stays dead, unless it comes into with +1/+1 counters if not then the answer is still the same.

Answer 3

1. No, your creature will not survive because it's toughness is reduced to zero.  Having its toughness decreased to zero is different than taking lethal damage.

2. No, his creature wouldn't survive since it took enough damage to kill it while it was in combat.