An interesting premise, but completely unsustainable and implausible. Even the simplest of things, the rabbits, are totally off-the-mark...where are the droppings, which rabbits do so often and without boundaries? Where are the bones that would be left from (allegedly) so many millions of dopplegangers eating them? They would hardly be as healthy and clean as they appeared after decades underground, anymore than the other "Us's" would be, and all of them would be quite effectively blind in the sunlight.
Where did the red outfits and similar shears come from? How could moves be matched-up underground where there's clearly not even close to enough room to mimic the above ground environments and open spaces? And, one of the biggest questions of all, if they mimicked every move that their doubles did above ground, then why did they stop and start acting independently? They'd all be like the little boy's DG and easily not only be avoided, but so simply destroyed as walking one back into a fire? Far too many elements like these are wholly impossible, much like the "power" of hypnotism used in Get Out, where it conflicted with the brain surgeries (they are not synonymous, nor could they ever be. Peele has some interesting ideas, but his development of them is just too much to overcome. I hope his next movie is more probable, as he does have some imagination, but that's about it. It'd be nice to see a black film that's not got some racist overtones or undertones someday, but this isn't it.