You've heard it before and it sounds like a cop-out but it's true: there are no answers to these questions. The only way to approach it is to consider your individual situation. If you have good grades, a Science paper, a PhD and a 210 step 1, your step 1 isn't going to matter much. As for program rankings, it is somewhat easier to come up with fellowship/subspecialty ranks, but even these wouldn't be universally agreed upon. But if you have identified heme as your fellowship of choice, then go to a program that has famous heme people. But if you're like most people and don't know, then going to a place that has the most good fellowships makes sense.
If you're a great candidate, no boards score, so long as it is passing, is going to really disqualify you. It might warrant explanation. Nobody really knows whether or not certain programs have actual number cutoffs, whether these numbers exist or are different for AMGs and IMGs, and how often they are ignored when the candidate has something else in their application. All you can do is score the best you can and apply to the programs you want to go to. If they don't want you, you won't get an interview.
I would add that while we do not have a firm cut-off, we do put a bit more weight on usmle scores than other factors.
According to my PD there is a correlation between low usmle (step 1 and 2) scores (regardless of other achievements) and RISE/boards performance. Since top programs strive for 100% pass rates and since the boards are mostly about whatever innate test taking skill allows people to score well on these types of tests, it makes sense that programs will rank with preference given to board scores, if they can afford to do so.
Frankly, the applicants I have seen ranked well all have good board scores (I would estimate roughly 230+ over the last 2 years), interview well (which is critical), and have some other achievement that stands out.