Unfortunately for us, the definition of reptiles doesn't hold in a fantasy world. My suggestion: it's a game, you have ten races, play them as you will and enjoy it. The game is the lore and there is no reason to argue over something this trivial.
Then the definition you looked up is wrong.
Im not sure about the present day, but I am 100% positive that in earths history there have been warm blooded reptiles.
Some dinosaurs for example. We know they had means of controlling their body temperature due to their sheer size. They must have had a way to control temperature and another to deliver extra oxygen to the blood, or they couldnt have existed at all.
Its not a big evolutionary advantage if your extremities get gangrenous and die off.
Furthermore, some members of the Selachii (sharks) have developed controlled body temperature and internal gestation (they give live birth.)
These tricks arent exclusively mamallian and you cannot define an order of animals that way. You cant say: it has this, therefore its not a reptile.
There are even flies that give live birth.
In the end, these distinctions are mostly about genetics.