Why not ask ?
Lots of Vicars today are women. Some are High Church, and may prefer Father, rather than Vicar. Some may be happier if you used their first name.
We had a woman Vicar near me a few years ago, and she was the first women incumbent ever. When she attended the local primary school, for their morning assembly for the first time, the Head Mistress said that they were a little nervous of how to address her.
She told them that her name was Mandy, so she was known to all the kids thereafter as Vicar Mandy !