Two of those aren't new things. I know of studies back to the 1980's about how people estimate 40% of the population is Black or Latinx quite regularly. Nobody has ever figured out the explanation for the first one, the latter did show some evidence that constant talk about the "Guaranteed Demographic Changes" boosted the number in the 2000s and 2010s. Most people believe the United States is already majority-minority even though 70+% of it remains white and the majority-minority scenario won't possibly happen until the next century.
The New York and California ones have been explained in prior studies about whether people just take in national news or from sources like The New York Times versus actually paying attention to or favoring local news. It's not unusual to see things that happen in NYC/Cali/DC turn into "national news" stories just because all the news media people are in those areas. I've found it's not even unusual for local news to cover those stories to the detriment of local coverage as if anyone who wants local news actually cares.
Twitter's bubble effects are well known, even though a super majority of people aren't on Twitter this continues.