I can't ID them - I can barely see them. Perhaps some closeups of the specific plants would help, or smaller groups of them.

About how old do they need to be before they start having adult looks

haha, I think they are too young to be IDed, unless they came with labels... So you might just have to patiently wait and see what they turned out to be.

1 year old Lithops would mostly have the looks of adults already.

Here's my yearlings pot from 2 months ago, not much has changed since then. Although few of them might be regenerating soon

{{gwi:640670}}

Wow those look nice I'm hoping mine make it to look like that being my first time growing these plants I don't know