I'm guessing I might have already missed the ranking deadline but as some who is celebrating my 10 year anniversary of fellowship match day in a few days, on the other side, I think there are some considerations that are missed in the above factors to consider.
The biggest factor should be places that can take your interests and demonstrate a way for you to gain expertise and develop a niche that's going to get you hired as a new attending in 3 years. Division Chiefs when they hire you want to know how you're going to secure extramural funding in 2-3 years as a new attending to get you promoted several years after that. The best fellowship programs will get you a leg up on that process. Yes the academic product is a checkbox to board certification but it's also there, at least in the current environment, as a runway for you navigate towards liftoff of a productive career. I'm in private practice, but even then, we have administrative contributions we have to make to the hospital and when we hired in the past, fellowship candidates with nothing clear to offer our group were readily passed over for other candidates. Every fellowship program is going to teach you how to put in lines, run a code, manage the breadth of critical illness and injury in children, that's the assumption that board certification garners you. The key then is how do the programs help you distinguish you from others.
If you have a mix of unit sizes, then consider it a factor, but that is something that I don't really feel contributes much. Every place I interviewed at was 26 beds or more, most closer to 35+. I dont' think there's that much difference between 30 beds and 40 beds, since most places that large are going to split the coverage with 2 teams.
I think the technology dependent unit question is reasonable, as that can really throw off acuity levels and be real annoying admitting your umpteenth stable, just needing extra O2 trach/vent admit for the day. Not that there isn't learning to be had with these kids, but if the pulmonologists have a place to park them elsewhere, that can have a dramatic impact on your experience.
While the classic fellowship schedule has been to front load the first year with clinical time, I do think there are reasons why one might weigh a more balanced schedule in which clinical time is relatively constant across the three years as a positive element. First, attendinghood is very much a constant grind rather than having big chunks of time dedicated to research/administrative tasks (minus those people in the lab hired specifically for their research output). Might as well replicate that from the beginning. Second, it's a super common refrain on interviews from the 3rd year fellows that they often found themselves scrambling to regain comfort clinically as they moved toward the back half of their third years and prepped to become attendings. A balanced schedule keeps those clinical skills sharp. Third, with all the talk of burnout and mental health in CCM providers I think there are arguments to be made that a balanced schedule reduces burnout potential compared to 10 months of q4 call in the traditional first year. I suppose others might counter the opposite to be true, and that easy years 2&3 may "cure" that first year burnout but I'm not sure how that translates into being an attending. Fourth, if you are in an interesting city, have a family, or otherwise want to have a social life, the balanced schedule is more conducive to that. I was super single upon starting fellowship and I don't think I could have any sort of social life in a traditional model, certainly not to the degree I did in my first year. I was in a very "fun" city and maybe in a different location, it wouldn't have mattered as much, but my top 3 choices were similarly large cities so it's hard to claim that personally, but I recognize that people are looking at all sorts of varied locations.
As for NP/PA's, a good fellowship program will clearly delineate the responsibilities. They should get to do procedures, but the understanding will be that first year fellows early on get first crack to build up experience. Remember residents want procedures too and so in the best set of circumstances, not all the procedures fall to the fellows.
Hope this is useful information from someone on the far end of this point.