If the Lobber Crew sacs first, then we need your blood is played to kill it, does it's ability still resolve?

Yes. Just removing the source of the effect does not cancel the effect.

Yeah.... Sac effects tend to end up being faster than anything since they still resolve. The only defense is removing the target of the effect from play, but with Rock Lobber it's a moot point.

Actually, to be completely accurate, in this case you can't even respond to the Lobber Crew's ability with WNYB targeting it. As soon as you announce the Lobber Crew's ability, you pay the cost - in this case, sacrificing the Lobber Crew - so it's not a legal target.