Just because someone is too lazy to look up a website on one particular day doesn’t mean they can’t handle Ivy League-level work or that they’re lazy in all aspects of life. I certainly consider myself lazy in certain areas of my life, and I have an Ivy grad degree I worked my butt off for. (Although it is true that you don’t always want to rely on information passed on from others; it can frequently be wrong.)
To answer the question, OP: Yes, every Ivy does require a high school transcript (and SAT or ACT scores) from transfer students. So do other top schools like MIT, Stanford, Vanderbilt, Duke, Amherst, Swarthmore, and Williams. (to be clear, I checked the transfer admissions page of each university/college to be sure.) The requirements don’t differ whether you are applying to transfer in as a sophomore or a junior. Most of these places seem to prefer sophomore transfers.
Transfer spots are usually created by students who leave a college before they graduate. However, very few people leave these top schools before they graduate - they admit only the best applicants so few people leave because they are struggling, and their student bodies are relatively affluent and they have excellent financial aid, so people rarely need to leave because they can’t afford it any longer. Because of that, there are very few slots to transfer into, and transferring is even more competitive than freshman admissions. You need to not only have an exceptional high school and college record, but evidence of leadership on your college campus and a clear, compelling reason for transfer. It has to be about your comfort and fitting in at your current college.
These universities also prefer to take students from peer institutions. Vanderbilt says it right on their transfer admissions page. The others don’t mention it explicitly, but I’ve advised some Columbia transfer students and the vast majority of them transferred from peer institutions.