I largely agree. I have one important concern however: this sequence hinges on the defeated army camp.
I believe this is an essentially Roman concept. Hellenistic armies were known to build marching camps, but nothing like the temporary fortresses the legionaries built every evening.
From what I read of hellenistic battles, camps were not places which you could defend effectively.
I would rather place the crux on the degree of disorder and the quality of (remaining) leadership in the losing army. If the troops hold together, they usually can withdraw relatively unscathed (not an easy feat, usually requires an elite core and/or exceptional leaders); if not, they rout and are massacred and/or dispersed.
Regarding the role of cavalry and light inf, I think the immediate aftermath can see all troops in order (including heavy inf) taking part in the slaughter, while light troops (cav and LI) would pursue, that means scouring the countryside and harassing the retreating columns.
The idea of keeping forces in reserve for the pursuit seems strange: I never read anything like this in this period. Reserves were rare in these times, usually meant to be used for an opportunity strike (heavy cavalry, see Gaugameles or Paraitakene) or to bolster a faltering part of the line (heavy or medium infantry, see Granicos or many Roman battles). When we read of re-deploying troops from one sector to another, it was usually taking troops from a quiet sector to shift them to another.
As of the role of the legionary camp, I would treat it as giving a bonus to a defeated Roman army to keep cohesion, but it would be of no use in a catastrophic situation: see Cannae, where the Romans were slaughtered in the open field.
MGR