Its not a bad plan. The crawler neck can give you all you need: its obscencely versatile, can do anything from free to slayer and do it well (the bridge less so, but still very much so).
I wouldnt go for a trill - I'd get an IT. No question, in my mind, about that. (But I'm more of a bucker guy, I dont know much about the whole single range; I've only used ITs, trils and an ubersinner bridge).
The NB gives me some concern in getting the jazz. But I dont really play jazz so who am I to say? I've just heard lots of it. Never tried to achieve the sounds. That said, you could also parallel that, and (if one of my c-bombs in parallel is anything to go by) you should get some good tones out of it. Its not as savage or aggressive as I'de personally like for Gojira esc tones (I'd go for a PK for that) but its a good bet for the balance youre after, imo.