You'll notice I have used no figures with horizontal pikes. These are, IMO, a bit of a pain to store or to use in a game as the sarissas stick out to an exceptional degree & stop an enemy from closing.
In reality though, that was kind of the point of pikes (pun unashamedly intended), they can attack us but we can't reach them. Could a phalanx be just the ancient equivalent of a WWII tank?
I do understand your need for bases to touch for the game mechanism.