+1 for power cleans. I like your thoughts on Auto regulation of the weight. The Practice in stepping to the bar, grabbing it and moving it upwards in a rapid manner to a rack position is so basic, and if it is too heavy you can't move it fast enough to rack it. This can only make you better in the dead lift. There is something stimulating in generating power(load x speed). It drives the other lifts.
I still fall back to the field of thought that if the novice is squatting to appropriate depth with the prescribed form that should drive the deadlift up along with the form practice with PC's and the 1 set of 5 dead lifts that progresses every time it comes around. I still think gaining a pound or 2 a week from here to 220 will put a tailwind on this case.
Rip has said he didn't deadlift save at competition either. He only did rack pulls and haltings towards the end.
As for the auto-regulation, I agree. But let's say someone just has complete shit for power potential. Will someone whose power clean is only 40% of their deadlift benefit as much the pull volume offered by power cleans? Or would it be better for them to speed deadlift at 60%? I mean this in the genetic sense, as in their power clean can only ever be 40% of their deadlift.
The point of speed deadlifts is to be fast. If you can't clean 40%, and it isn't a technique issue, you probably can't pull 60% fast, either. At that point, what you're actually doing is light volume deadlifts. Nonetheless, speed deadlifts are more specific so the argument could be made either way. In the context of "SS", it is wise to do the cleans.
I think the takeaway point is that if you're dead-set on doing SS, do the cleans. Not enough pulling volume without them.
I personally don't actually think the novice program is ideal for novice powerlifters for a variety of reasons: doesn't introduce the sumo deadlift, doesn't introduce competition technique, it has equal overhead to bench frequency and volume, too much squat volume, not enough pulling volume, and not enough upperback work (this is debatable, granted). Then again, the novice program is not intended for novice powerlifters nor is it intended specifically to increase 1RM in the powerlifts.
I think the squatting volume is fine - as long as the weight is going up. Sumo is only relevant if sumo is what you'll end up using, and I think a novice PLer should at least start conventional. But I think the rest of your points have some merit.