1)
Why is the latter Yud in "Avigayil" omitted?
1.
Radak citing Yerushalmi Sanhedrin 11b: It was improper to hint to David, while her husband was alive, that he should marry her. Therefore, her name is deficient.
2.
Radak: This is close to Avigayil. She was called both ways. There are many names like this.
2)
How did Hashem send her?
1.
Radak: He put in her heart to go to greet David.
