Suppose Alice has Moss-Pit Skeleton and Skyclave Shadowcat in game and Bob has a Kazandu Stomper (or some other strong creature, it does not matter).
It is Bob's turn and he attacks with his Kazandu Stomper. In return Alice blocks with Moss-Pit Skeleton. After blocking and before damage is dealt she wants to sacrifice Moss-Pit Skeleton to Skyclave Shadowcat (knowing that Kazandu Stomper stays blocked but no damage is dealt and Kazandu Stomper isn't damaged nor killed, that does not matter here). Her plan is the following (and here is my question, i want to get sure whether i understood everything correctly):
- Skyclave Shadowcat's first ability is activated, mana is paid and Moss-Pit Skeleton is sacrificed as additional cost of this ability.
- Moss-Pit Skeleton is placed in her graveyard because of the cost of Skyclave Shadowcat's first ability.
- Skyclave Shadowcat's second ability is triggered, as Moss-Pit Skeleton had +1/+1 counters on it and Alice therefore draws a card.
- Skyclave Shadowcat's first ability resolves and it gets a +1/+1 counter.
- A +1/+1 counter is put on one of Alice's creatures and Moss-Pit Skeleton is in her graveyard, therefore Moss-Pit Skeleton's last ability triggers and Alice can put it on top of her library.
I am especially unsure about the last point. In short: Is it possible in this case to sacrifice Moss-Pit Skeleton as part of the activated ability cost of Skyclave Shadowcat and directly afterwards put Moss-Pit Skeleton on top of the library when the activated ability of Skyclave Shadowcat resolves? Or is there some waiting mechanism that places Moss-Pit Skeleton only in the graveyard after the ability of Skyclave Shadowcat is finished?
In even shorter: Is Alice in this case allowed to put Moss-Pit Skeleton on top of her library?