Regarding the survivor situation...
The thing is, with a survivor, you lose lylo. Scum claim and force survivor to vote with them, otherwise they night-kill survivor.
So, you lose at 7. So, you have 9 players (1 confirmed survivor), and need to hit scum or lose. Or you could lynch the survivor and go to the 7-player lylo. So, town should lynch survivor. (note that survivor at 9 players could care less which side is lynched from a win-con perspective, which is all the more reason town should lynch them).
Of course, then, you could have lynched them at 11 players, and had the smaller town, improved scum chances situation for 9 players. Etc, back to day-1, why didn't you just lynch the survivor day-1? Because it feels bad to just force a single player to lose, when they don't have to. But the fact is that it hurts town not to lynch that player.
So, in the end, I think town should lynch a survivor day-1 because it improves their chances to win. Feel bad about it if you like, it sucks to be the survivor, because it's a crappy role.
But, really will town do this? I dunno...as I said, hard to lynch someone and make them lose to improve your chances of winning. Especially given you can win together if you just play the deduction game better. I'd lynch them though, because I play the probability game pretty hard (i.e. I prefer the game-theory side of mafia to the scum-hunting/social deduction side).
Scum won't NK a survivor, so claiming at least benefits the survivor on that side.
Regarding IC-timing-claim-issue.
We also have potential protective roles, which make earlier IC-claims better (because they can be protected, or at least NOT NKed for fear of protection).
Hmm...okay...IC-claim-timing theory: I think it's (perhaps entirely) dependent on the player. Some ICs are better "directors" (i.e. can be really effectove as known ICs). While other players might be better as "detectors" (i.e. finding the scum based on interactions when the IC is unknown).
Like, for ash, delayed IC claim is probably more powerful, because he's really good at figuring out who scum are, but appears super-scummy himself.
For TA(I think?) it might be more powerful to just claim early, because he's just very effective as an IC, directing town and stuff. (basing this off comments from the last blitz-game, might be wrong).
Anyways, that's my thought on it. Just don't get shot by the town-vig