I remember reading about mortals existing before the Dragon God of Time had solidified time into a continuous flow during the Dawn Era. How would it even be possible for mortals to exist during this time and what would it have been like to exist during such an age? It mentions them procreating but wouldn't mortals not age during this period and so not need to or not even be able to? Do similar happenings occur during Dragon Breaks?

Time existed, it just wasn't solidified into a linear state. IIRC, the dragon god was the first being created in the Grey Maybe. Time was there, but the idea of cause and effect was out the window.