To answer the first part: only a linear motion of the wire results, in the case shown it moves away from the viewer/reader into the page/screen.
To the 2nd part - yes ,motion of the wire will develop a potential at its ends, B2 can be <, =, or > B1, (except as per the below).
To the 3rd part - if an external force acts on the wire, this will change the potential at its ends also. Moving the wire in the same direction as B1 does not do this, so it is related to the sine of the angle to the direction of B1, if the wire rotates about its own central axis there is no effect, if it is rotated about an axis such that it is effectively crossing B1's lines of force at right angles then the effect of this motion is maximal.
Hope this answers your query, Regards, Orson Cart