Conan have some cool influences and ideas. There's those sludgy bits, but also stoner doom bits, and straight up heavy metal bits.
Yeah I love having conversations about music too, hoping this sub becomes a good place to do it!
There's a couple of funeral bands that lean more into the death metal influence for certain songs and can get faster. Ahab and Esoteric come to mind.
For guitar "feel" matters so much more than anything else so go with your heart/fingers.
I like humbuckers and they are the more standard choice for big fat doom tones, but single coil pickups are cool too especially with fuzz. I like Stringjoy strings personally so that I can get weird and specific with gauge/tension, but if you are going for D-C tuning somewhere between 52-56 is the range I would use. For reference I run 60's for my drop A non Gibson scale length guitar. As for what tuning to use I'd offer that with C# standard you can play so many great Sabbath riffs, and with the turn of a machine head you've got access to drop B.
Definitely get a Behringer SF300 pedal. It is a cheap copy of the Boss FZ-2 Hyper Fuzz and will get you that Electric Wizard tone. The ProCo Rat itself is pretty cheap if you have those available. Other suggestions are anything in the big muff family, for a cheaper option there the TC Electronics Honey Pot is basically a green Russian muff to my ears.