It isn’t a back door, but it does have a significant ED “bump” - 33% acceptance rate for the ED cycle, vs. 9% RD. I don’t think anyone is trying to say it’s a back door, just that it could be a more fruitful use of that one ED spot, and therefore it deserves a look.
I understand the impulse to rule out women’s colleges without looking more closely. But schools like Barnard and Scripps, that have such close ties to co-ed institutions that basically everything is coed except the dorms, are worth looking at with an open mind before ruling them out. (Although in this case, it’s unclear whether there’s an affordability differential between Barnard and Columbia, and it’s not really confirmed that either one works financially.)
Re: the URI and merit aid question, I have seen a number of kids on here get enough merit from URI to get to cost-parity with their in-state flagships. (There are a few full-ride scholarships too, but I haven’t seen anyone post about getting one.) The few that I remember well enough to look back at had similar grades but more like 1500-ish SAT scores. So I wouldn’t necessarily count on in-state level costs, but it doesn’t seem unreasonable to hope for “in-state plus 10K.” But my impressions come from a pretty small sample size; hopefully there are others with more experience who can chime in.
ETA: Never mind about the test scores - I don’t know if this is a recent change, but standardized test scores aren’t considered for merit: https://web.uri.edu/admission/scholarships/ It’s based on weighted GPA as recalculated by them, and course selection. So, I would think a full-IB student with a 3.9UW would be pretty well-positioned.