A snake 2" long is NOT a copperhead. They're around 8-10" at birth. A (harmless) worm snake is tiny but still around 4" at hatching. The (harmless) brown snake, or De Kay's snake, is maybe 12" as an adult so similarly very small as a juvenile (I think live-born). I'd like to see some photos. Either you can't estimate length very well or the whole "bunch of copperheads in house" is just wrong. I've observed and caught literally hundreds of venomous snakes in the wild and in captivity and have to say this story cannot be accurate in its entirety. The initial two adults might have been copperheads, the ID on those is pretty obvious but the little ones sound much more like brown snakes or something like that. Baby harmless water snakes and garter snakes are also rather smallish (still 6" or so) but have an attitude, striking like crazy, and can be present in numbers since the females can give birth to over 20 offspring each which could come through a 1" door clearance easily.