Sacrifice a nameless inversion??

Question

I sometimes run a BG Beast deck that uses ravenous baloth and nameless inversion. If I were to attack with my ravenous baloth and my opponent declares a blocker, could I use nameless inversion to kill it and allow damage to go through?

Then could I sacrifice the instant, which has changeling, using the ravenous's effect before it reaches the graveyard as if it were any other beast with invoke?

Answer 1

No because it is not a permanent, it would have to be some sort of permanent either creature, enchantment or land.  

Answer 2

1. You can use Inversion to kill the blocker before damage, but unless you manage to give Baloth trample, it will not deal anything to your opponent. Once a creature is blocked, it stays blocked for the rest of combat... even if the blocker is killed.

2. You can only sacrifice permanents. You cannot sacrifice a spell, so no.