If I play a card with the keyword "reversal" on it as a normal attack a can I use Lacks Viture E? which is

E Commit Remove X caffeine tokens from this card: Your reversal gets plus X damage.

Also if a multiple attack is coming at me, and I block the first one, and reversal it, and it drops the opponent to 0 life does the player die before the other mutliples go through or do we have to resolve the other multiplies

Yes you may use the enhance, because the attack has reversal printed on it. It does not matter if it was actually played as a reversal.

Your opponent would drop to 0 life, and you will have won the game. Their turn will not continue.

Stamp for Ender.

One quick additional clarification: the reason Lacks Virtue works fine that way is because it just says "Your Reversal". If an ability says "your attack played as a reversal", it's looking for more than just the keyword (in fact, in this case the keyword is irrelevant since it's possible to use abilities to play an attack without the keyword as a reversal sometimes).