Since people are talking about kobolds in their settings, on Dragon Earth kobolds are descended from rhesus macaques from southern India. To further confuse matters, they get along famously with gnomes.
I do know an Aussie who made his kobolds klingons. Part of the SSGCLA (Slavic Small Giant Class Liberation Army). He also had dragons with howdahs running around. (Long story.)
As to therapsids etc.: Last I heard therapsids et al weren't even reptiles. Heck, the first reptiles weren't even reptiles. The progression now is: Amniotes (first animals to produce egg shells) from which first the synapsids and then the diapsids (modern reptiles and crocodilians) split off. The synapsids gave rise to first the pelycosaurs, then the therapsids proper. From the therapsids you get the proto-mammals and then mammals themselves.
As far as I can tell it would appear that turtles aren't proper reptiles. That designation is reserved for lizards, snakes, and mosasaurs these days. Other former reptiles include thecodonts, pterosaurs, pterodactyls, crocodilians, saurisuchians, and ornitheschians. Aves is incorporated into the saurisuchians nowadays.
This schema is subject to change without notice.