Re: LIL 59 for metal
Well, it's not a high-ouput pickup like the Hot Rails or Distortion, so in theory (I don't have one), yes. But again, it depends on personal preference and how you define "clean up well". If you want Clean Channel on your amp and "absolutely no grit from the pickup when on the Clean Channel", then as a humbucker, you might find more beef in it than you want. Split to single-coil, it won't sound exactly like a single coil, but it'll be "close enough" (i.e. 60-cycle hum, not as beefy as a humbucker, etc), but it also depends on what exact single-coil tone you're going for - Texas Special? Vintage 50s? TexMex?
On the other hand, since it's not a high-output pickup, when you back off the Volume knob on a Distorted Channel on your amp, you will notice a reduction in Distortion level because you're reducing the amount of signal going into the amp. Only you will be able to tell whether or not it sounds good to you.
Not trying to be an ass, but these types of things are entirely personal preference. It's impossible to get a definitive answer as everyone has different preferences. The most you can do is take an average of stated preferences weighed against each respondent's choice of amp, guitar, and playing style, and then flip a coin.
It's the same with amps and guitar body styles - a Roland JC120 is perfect for Metal, if you have a <insert name/brand/type of pedal/rack/preamp> running into it. A Gretsch White Falcon will sound just like James Hetfield's Gibson Explorer on Master Of Puppets, and a Jackson Warrior will sound just like Keith Richards' Rosewood Telecaster with the right EQ and amp settings.
It's all too subjective to ask that question.