What a difference five months make to cacti seedlings.
Here they are in May:
And here they are today:
And a couple of close ups....
Any IDs or advice for care over winter would be most appreciated.
They should successfully overwinter in a cool (40-55F), dark, dry place. An occasional misting may be beneficial to prevent these juveniles from drying out too much.
I'm guessing the really white ones are Echinocereus baileyi and the remainder are kinds of Mammillarias. The less glossy green one below the rock in the "here they are today pic is difficult for me to make out.