I think for the "what is normal?" topic, we first should ask, what do we mean by saying something is normal? I assume we want this as a go-to list for closed normal games. Like, these are the things you can expect.
Why do we need that? Because when signing up for a normal (closed) game, I don't want to worry about stuff like "maybe if I vote more than 5 people on D1, someone has a role that will instantly kill me for that".
All roles in the first category I agree are well established enough that I don't mind them being normal. For the "open for discussion" list:
Bus Driver - means all roles have to worry about not hitting their intended target. I love Bus Driving, but this introduces a major thing to worry about.
Redirector (and all variants) - same as Bus Driver. But at least having only Bus Driver limits the damage that can be done.
Voyeur - I don't think this introduces a big new worry. It makes it slightly more dangerous for scum to fakeclaim, but not by much.
Lightning Rod - never if you cannot choose to activate it, and even if you can this it too big of a manipulation thing in scum hands. I would exclude it.
Nexus - same.
Janitor - once the Janitoring happens, everyone knows that the role is in the game, so I don't see much of an issue.
Coroner - if Janitor can be in, this can as well.
Survivor - I don't like Survivors much in general because they tend to swing the game towards the faction that is already winning. There's no real reason to exclude it though.
Mime - definitely too big a worry for all players involved. Out.
Lyncher (and other vote-based roles, like Actor, Hammerer, etc.) - no.
False - this is mod lying and Bastard. No way.
Hidden - same.
For Miller, I don't see why not include it when Godfather is already included. The effect is the same: it weakens the Cop. I even like it better than Godfather because it means the Cop cannot 100% catch scum. And let's face it, situations where scum is 100% caught are not fun.
It might be worth it to look at mafiascum normal roles. There's a couple of things there that are not listed here:
Bodyguard, Commuter, Follower, Gunsmith, JOAT, Motion Detector, Neapolitan, Neighborizer, Rolestopper, Universal Backup, Vanilla Cop, Friendly Neighbor, Encryptor, Traitor, Investigation-Immune, Ascetic, Enabler, Even/Odd Night, Macho, Non-Consecutive Night
PPE: 2