In case of projectile motion,
i) P.E is maximum at the highest point.
ii) K.E of a projectile will be minimum (but not zero) at the highest point, because only vertical component of velocity is zero. K.E is maximum at the place of projection.
iii) Total mechanical energy is conserved at all location of it's motion.
A particle can be projected in two different ways to make them fall at the same distance.