I could clearly see Ciri’s green eyes at the beginning and at the very end.

She is a Witcher, i believe Triss and Gerald were able to find the mutigen needed in order to do the trial of grasses. In the show it came from Ciri’s elder blood

Im interested to know the timeline too, and if Geralt really did retire with Yen.

I had always assumed Ciri would eventually become a Witcher, given her elder blood and fate tied to Geralt.