Cactus Game Design Message Boards

Ahimaaz's ability must complete, so yes, you get to look at their hand and withdraw if you want before they can negate it. If they do decide to negate it, it's not really like you can forget what's in their hand, and the withdraw ability has already been skipped.
You can prevent a withdraw ability though. Perhaps they rescued with another hero, and tried to band in Ahimaaz with Numerous as the Stars. Ahimaaz couldn't withdraw in this case.
The battle takes place. Should you withdraw, things like Chariots of Fire works (following Rescue Attempt).

Unless you use a card that negates him before battle, such as Confusion of Mind, Image of Jealousy, Destructive Sin, etc... then yes, you cannot stop him from leaving battle.

I dont know why it is ruled that after Ahimaaz/Rhoda/ect withdraw from battle that the battle automatically enters battle resolution and then discard phase, but it does. That seems like NPE to me...

There is no hero to block. When absolutely nobody is in battle, there isn't much of a battle to fight is there?

You can't block a hero that isn't there. He's in territory. No hero is in battle.

Spy + Spear I disagree with, but the ruling was "Did it enter battle?" "Yes" "Was it negated" "No" "So...do what it says."

They do. The one can't block because no hero is in battle, the other didn't want to battle anyway, so they're done. Unknown Nation says "If an opponent's hero is in battle" and Am Slave can't block a hero that isn't there.

Except for the Taunt ability, Evil Characters cannot enter battle if there is not a Hero present.

Argue all you want, that isn't going to change.