#1
I have an alnico humbucker at the moment, but I play a lot of experimental, screamo, post hardcore stuff.

Would P90 be better? I'd be putting in the Gibson P94, as it's the humbucker version of the P90.
#2
Stick with the humbucker if you play screamo/anything with a bunch of distortion.
There once was a man who really loved salt
So he tied his nose to the sea
And then God came down from his silver throne
And said, 'Honey, that water ain't free