did leah imprinted on sam before he met emily?

Nope...and if you've seen Breaking Dawn...there is a scene where Leah tells Jacob she wishes she could imprint on someone so that she could break the connection with Sam.....poor Leah....

No, they were just in love. Leah was not a بھیڑیا yet and so did not have the ability to imprint yet. Besides, it is possible to just be in love with someone without imprinting.

No! Leah just love him like Jacob loves Bella.

No, she just wishes she could could imprint on someone else to forget Sam as she told Jacob in the movie.

No. Sam imprinted on Emily, that's why Jacob کہا to Bella in New Moon, "Welcome to the Leah, Sam, Emily fest." Sam did like Leah, but could not commit to her, for he had already imprinted on Emily.

no.......................................

No, they were just dating normally. Leah hadn't imprinted on anyone as of the end of the series.