Vilgefortz

So I have questions about Vilgefortz plan cause it’s really creepy and confusing.

1. Why does Vilgefortz want to artificially impregnate Ciri, who is like 12 from what I’m told. How is he going to get her powers that way?

2. Why did he specially choose impregnating females to get Ciri’s powers?

3. Doesn’t females can only use powers of the Elder Blood? How can Vilgefortz’s use this power if he is not women?

Soo i was reading the part with Vilgeforts/Regis/Yeneffer/Geralt fight. And i have a question. What did the medallion that Fringilla gave Geralt do to confuse Vilgeforts. Afterwards Yeneffer says that she didnt know that Geralt can do ilussionist magic, of course in a sarcastic way but i dont exactly know what the medallion do.