#1
which humbucker is the best for splitting it to make it sound like a single coil (aka strats neck pu)

I would be putting it in a schecter c-1 +
#2
any 4 conductor pup, for a coil split

consider a P-90 too
Get off this damn forum and play your damn guitar.
#3
SD '59 sounds pretty good. Probably gonna through that into my C1 Classic soon.
Gear:
Gibson Explorer (white)
Schecter C-1 Classic
Fender SuperSonic 112
Visual Sounds Jekyll & Hyde
EHX No.1 Echo
Ibanez Weeping Demon
#4
The Rio Grande tallboy is two strat single coils put together for a humbucker, so I would expect that to sound the most authentic.