I think it depends on where you are. I'm in Texas, and I'd pronounce it with two syllables because of my accent. I think the proper way is with three syllables, though.
Friends of ours named their daughter Avery and pronounce it as Ave-ry (two syllables only).
I've never heard anyone pronounce it with three syllables. It might be a regional thing, and I've always lived in New England, but if I were to hear someone say it as AY-ver-y, I'd think he/she were enunciating to the point of being awkward.
I think it depends on where you are. I'm in Texas, and I'd pronounce it with two syllables because of my accent. I think the proper way is with three syllables, though.
Same. My first instinct was to say 2, but I know I say it incorrectly.
I pronounce it with two. There is a girl named Avery on Dog with a Blog (DS1 loves those tween Disney shows). I think they pronounce it with two on there; I will check if it's on later today.