She’ll have no problems with the pre-reads at Ivies if it gets to that.
As far as timing, I’d really ask the coaches about their timelines and when they make those decisions. What she should be listening for in the response is not a general rule but how they’re responding to her asking the question. She’ll be able to infer some things from that about the likely level of interest and how long she might have to wait.
I used to be pretty confident saying Ivies are making the bulk of these decisions over the summer and into the fall for men, and only after an OV in most cases. Recruiting classes for women have tended to coalesce a bit earlier because the growth curve is often flatter late in HS. My impression is that a lot of this is shifting earlier but it’s somewhat program dependent. Maybe others with athletes in these programs or more recent experience can help with a typical timeline. I’m guessing Harvard, Princeton, and probably Penn already have their priorities largely figured out for women.
As for lukewarm interest, sometimes lukewarm can get hot pretty fast and it’s just a function of attention/bandwidth. Many of the D1 programs are at regionals this week, then nationals, time off, getting back to the office and focusing on recruiting.
As far as D1 vs. D3, I wouldn’t divide things up that way. Compare Colgate to Williams for example. Colgate’s fastest 1500 would be 6th fastest at Williams. Different story at Harvard though.
What I’d focus on is whether there’s a training group that fits and enough range on the top end to allow for the kind of working up the ladder you mention (and which I agree is important).
Another thing to keep in mind is that in college not everyone gets to compete. A lower level recruit at an Ivy might not get many chances and might be attending the conference meet as a spectator. This depends on the specific program though. Brown is different than Princeton or Penn.
I definitely wouldn’t encourage an athlete who could compete at the conference level at an Ivy to go to a NESCAC as it’d get pretty lonely during workouts. But for someone who would be on the bubble to compete consistently at an Ivy vs. a regular meet schedule and probably conference competitor at a D3 I’d probably prefer the latter if the school fit was right. It really just depends what she wants.