So that means at least one scum in {e, PPS, Joseph, WCD, Space, ingathief}
Not necessarily, right? Since it was a plurality instead of a majority, there were 6 other people with different votes in addition to Robz and faust. Once Robz lynch was assured, both EFHW and hyper jumped off and onto a wagon they knew wouldn’t make. The same with mcmc, Dylan, Awaclus, and DatSwan (not the jumping just the being on wagons going nowhere). I don’t know why scum would leave themselves on a town lynch wagon when it was going to make regardless. The VCA works much better when a majority is required to lynch.
While you're technically right, it would certainly be a surprise if there were no scum at all in that set. In the run-up to deadline, we usually end up voting to try to get a lynch through, and the idea of getting someone to claim before lynch had been discussed earlier, so I think that was on most people's minds. So scum probably didn't want to risk being off-wagon entirely in case random panicked townie votes settled somewhere they liked less.
For me, e is quite a strong townread, and given that Robz is IC, then PPS and Joseph are the two most likely scums. Probably not both together, though, because they joined the wagon in very quick succession (posts 404 and 405 respectively, which EFW joining at 415 as the very next vote cast) and that's an unusual voting pattern for two scum-buddies.
The other evidence from my PoV against Joseph is that he's sat with two known towns on his wagon for a while (me and faust, from #124 till faust moved at #247) and not picked up a scum trying to push a mislynch on someone who might have been quite an easy wagon. Later on, e and I are both on him with no further traction, though by that point EFHW and WCD have bigger wagons anyway.
I'd also say it's likely that at least one of Joseph and infangthief is a townie, because if they were both scum, I would have expected Fang to hope off the bigger wagon that picked up on Joseph around #381.