Maulerfiends move 12" and ignore terrain. They'll be in people's faces just as quick as the talons or the prince.
Yup! They're actually the fastest walker in the game.
I don't believe I need cultists, they're not good, and easy to kill in small, objecvtive holding groups.
I think you'd be surprised how durable they actually are. They can go to ground, and are usually ignored since the rest of your army has juicier targets.
6-8 vehicles? I don't agree with needing a ton of vehicles. It comes down to needing to play test the list to trim the fat and perfect what I bring.
Yup. I disagree drastically with mynameisgrax. Bring what you need, and don't have an "lots or nothing" mentality about any unit. Lists of all variations work perfectly fine.
I really hadn't thought of flyers, actually. I have no idea what to use to take them down.
Typically you can just sink 100 pts into an Aegis Defense Line with a Quad Gun for decent flyer coverage, but honestly it's really not enough (you could take Flakk Havocs). Unfortunately most armies only have that single option available to them so for some armies that's all they get. Try it out and see what you think.
Interesting about the champion, I'll have to check that out further.
They're absolutely correct. He cannot have a Blastmaster or Sonic Blaster for that matter (but he CAN have a DOOM SIREN!!!!). The entry for Noise Marines clearly lists options available to "Noise Marines" and separate options available to the "Noise Champion".