1) No it's not similar to preseason polls. There are lot more moving pieces when it comes to ranking a team than when it comes to projecting individual performance. "Is this guy going to rush for such and such yards again?" depends on an offensive line and some resemblance of a passing game. "Will this team be a top 10 team?" depends on running game, passing game, run defense, pass defense, schedule and coaching.
2) The whole "Big 12 defense" narrative is so overrated. Big 12 offenses get their gaudy stats the same way Big 10 defenses get theirs. It's all about style of play. As a whole, Big 12 defenses are marginally worse than most other defenses in the same way that B1G offenses are marginally worse than most other offenses. If you want to pull out his stats against the worst teams on the schedule, that's fine, but then you have to do that for every running back in the country before you compare. Also, I called him borderline elite, not elite.
3) At a position that is the most inconsistent from a stats perspective, Lazard was pretty consistent. In 11 games, he had 6 outputs between 66 and 87 yards. He had between 3 and 8 receptions in every game. He was never shut out of a game like receivers often can be. For a true sophomore, those are really good numbers. He is far from his ceiling, so natural progression should be assumed.
4) Comparing Lanning to all other Big12 QBs is foolish because ISU doesn't run the same style of offense as Baylor, Texas Tech, Oklahoma, etc do. They ran about 5-10 plays less per game. That's essentially 50 less yards over the course of a game. The average comp% in the Big12 was 58% last year. Despite it being a league that "opens its arms" to opposing QBs, Lanning was slightly below average. Making up for that difference is his production on the ground. Mahomes was 2.4:1 last year, Rudolph was 2.3:1, and Howard was 1.85:1. Lanning fits right into that group in that regard.
I think your biggest issue with this point is that you think I'm suggest Lanning is an elite QB. I'm not whatsoever. He is pretty average. I'm claiming that combined, the trio is one of the better in the country, not the individual pieces necessarily. If you disagree, oh well, I'm over it and really don't care.