It is supposedly very difficult with the Prunus genus, and that is partly why they are almost always grafted (also because this allows for choice of a specific rootstock). One time I got some dormant hardwood cuttings of cherry to callus up beautifully in a ziplock bag stuck in the garage over the winter, but they never grew any roots after I potted them up. I would guess that air layering might be more successful than cuttings though.

Depends on the species and cultivar. I've stuck cuttings of P.angustifolia "Guthrie' in the ground in March and had them root. Never tried it with any others.

I've tried and none took...I'm thinking some of the vigor root stock like prunus americana and nigra might work by layering but these readily sucker and can be transplanted like this.