The first way is with three noncolinear points. All three lie in the
plane that is formed. The second way is with a line and a point in that
line. The line must be perpendicular to the desired plane, and the point in
the line must be in the desired plane as well.
Yes, but only one of the points will lie in the plane. The two points must be
used to form a line. This line must be set perpendicular to the desired plane,
and the plane must contain one of the two points given.