On the Death Metal , usualy the bass should be cranked up , the trebles lower than halfway , and control the heaviness from the mids. (don't crank the volume from both the pedal or the amp, if you want the speakers to live longer)
Higher mids would give you an old hardrock kinda distortion which is also very good for leads if you got a nice reverb to go with, and lower mids would get you into the death metal tone (try increasing the trebles a little with that).

I don't have any of the other pedals you have , but generaly speaking for flangers and phasers (and vibratos) , you adjust the speed and depth to your preferences and that's it.
Delays can be tricky if you dont have the experience , keep tweaking and you'll eventualy get what you're looking for.

You should connect these pedals like this:
Guitar-Wah-Distortion-other-Amp
You can try different setups , but generaly most people like the wah before the distortion.