Excuse me, but Skoutatoi are after Heraclius' period.

Normal phalanx, as we know it, it's definitely out of the period. The spearmen Heraclius' used were a sort of Roman Lanciarii with modified equipment, and trained differently, because they were the backbone of the army.

Rosacrux, Swiss Pikemen really formed a modern phalanx, trusting their pikes just like a phalanx, and on their flanks, they had musketeers to guard them.

A shield wall is totally different from a phalanx. A phalanx is a mass of 6m spears or iron Sarissa and men, gathered tight, to attack and defend at the same time. A shield wall is a complex "wall" of spears, which is much vulnerable than the phalanx, but much more mobile.