I used to be in a metal band so I might be able of offer a piece of advice or two.
For one thing, forget about what your guitarists' EQs are set to. You play in a different frequency range and probably have a completely different set of frequencies dialed into your amp than they will. Just focus on your sound. And in this case, I would recommend boosting mids. In my experience you sometimes have to play around with the mids quite a bit to get the exact sound you want because it will sound weird at first. But once you get them dialed in, I've noticed they can punch through like a laser beam.
Another thing is to watch how much bass you dial in. I was always a fan of booming, low bass tones in songs but it's easy to dial too much low end into the sound and muddy everything up. Metal requires a certain tightness to the bass in my opinion so dialing it back a bit might take a little boom out but add a lot of clarity which may help. You may even notice that you can dial more bass back into the sound as you adjust the mids more. I generally save the treble adjustment for last as it's mainly an accent on the attack, but if you are playing up high a lot, you will need to spend more time there.
I highly recommend a 4x10 cabinet (or two). Your guitartists will endlessly whine about how loud it is even before you plug it in the first time, but you can remind them of the volume knob on your amp. They are correct, though. 4x10 cabinets are loud and produce a very tight sound without compromising low frequency fidelity. I owned a Hartke 4x10 cabinet when I was in my metal band but gave it up to my replacement. Right now I'm running through an Ampeg 4x10 and am quite satisfied.
As for note selection, I'm not a guru in music theory so I'm not sure I can help you there. Metal does have the bassist following the guitarists a lot, but I tried to mix things up when I could. If you have a 5-string, one thing you can do is translate some parts down onto the lower notes you now have access to. If you are already down low, then adding octave accents is a trick although very common. You can also experiment with duplicating chord shapes at various places that match what the guitarists are doing. Sometimes inverting the notes in the shape makes interesting sounds. Don't be afraid to experiment while practicing and remember to pay close attention to the drummer.
Lastly, don't worry about using a pick versus your fingers. My honest recommendation is learn how to do both proficiently because it will make you a better overall player, but if you don't want to dedicate yourself to that, then just use what's comfortable to you. I am fans of bands in the metal genre that have both pick and finger players so I've never understood why anyone cared, really.