Responses

Actually (if I remember correctly) it’s the same mate for all dragons! (It’s not a one human mate/one dragon ratio)
“Mates” are basically humans with a certain potential, so several can exist at the same time but in this era it’s only Eyra. You also don’t need the human mate consent for them to become your mate so all dragons are ready to fight for that booty even tho Eyra already choose Yanu, they don’t care.
If i remember correctly, the reason why despite the fact that Yanu's heart meter always increased yet the countdown of solath gettin destroyed is still counting is because of the dragons themselves.
Other dragon would tried to snatch or basically (forcefully) take Eira away from Yanu, meanwhile if i remember correctly, dragon can only have one mate throughout their lifetime, and dragon would literally fight to death, they're not gonna stop until one of them is basically death and they're really really territorial.