And which is most likely to accept them?
That’s too broad of a question. I would say all would be accepting. Where you would be accepted depend on stats and resume. HPY are toughest. Probably Columbia and Penn next but all have admission rates of 10% or less. Penn has a bump for ED but you need to be sure they will give you enough aid to afford it.
HPY are the most generous but that matters more for middle income than low income. Run the Net Price Calculators.
You can look at the Common Data Sets, which would show the percentage of minorities at each school. This, https://www.nytimes.com/interactive/2017/01/18/upshot/some-colleges-have-more-students-from-the-top-1-percent-than-the-bottom-60.html, has some information on economic diversity.
Well, here’s a breakdown of what percentage of the student body is from the bottom 20% of earners in the U.S., and how it fares in comparison to selected elite colleges/universities:
Harvard: 4.5% (among the highest)
Princeton: 2.2% (among the lowest)
Yale: 2.1% (among the lowest)
Columbia: 5.1% (among the highest)
Penn: 3.3% (about typical)
Dartmouth: 2.6% (among the lowest)
Brown: 4.1% (about typical)
Cornell: 3.8% (about typical)
However, higher numbers don’t necessarily mean you’re more likely to get accepted - there could be a lot of reasons for the higher rates at Harvard, Columbia, and Brown that don’t have to do with likelihood of acceptance there.
As for which ones are most welcoming - well, there are a lot of factors that go into that. There are more students like that at Harvard, Columbia and Brown, so one might assume that may enhance comfort - but it may not. Elite schools have been criticized for admitting these students but not fully supporting them in adjusting to a completely different culture.
With each of the ivies reserving around 17% of the class for first gen, I’d say all are welcoming and competing for the best of the bunch.
URM, recruited athlete, legacy, and first gen. These are the hooks of today. If you have any one of these with top stats your chances at any ivy are much better than the average applicant with top stats and ECs alone.
Don’t limit yourselves to Ivy. Take a look at Williams. They have a great outreach program to recruit first gen URMs.
In my experience, what a first gen low income student should look for at any of these schools is good financial aide and support. Many first gens I have met were standouts at average to below average high schools. They have the ability, but they have not been through the crucible that other students went through to get there. They have to improve their study skills quickly to be successful. Unfortunately, many of them have never seen students like their new classmates and have no idea what is coming.
Be sure to ask about preparation and support and please don’t wait until you are behind to utilize it. We all want you to succeed, and you can, if you get support early on.