I'd say that the Helios in the Myrmidon was either an Easter Egg or joke of some kind, so it probably shouldn't be used as a basis for some sort of Anti Sathannas Strategy. The Harpoon, however, was probably quite deliberate -
$Name: GTF Perseus
+Gun Mounts: 4
+Missile Banks: 2
$Max Velocity: 0.0, 0.0, 80.0
$Rotation time: 3.3, 3.3, 3.3
$SBank Capacity: ( 40, 40 )
$Shields: 350
$Hitpoints: 265
$AI Class: Captain
$Afterburner: YES
+Aburn Max Vel: 0.0, 0.0, 140.0
+Aburn For accel: 0.8
+Aburn Fuel: 330.0
+Aburn Burn Rate: 60.0
+Aburn Rec Rate: 25.0
$Countermeasures: 40
$Name: GTF Hercules Mark II
+Gun Mounts: 4
+Missile Banks: 2
$Max Velocity: 0.0, 0.0, 55.0
$Rotation time: 3.8, 4.2, 3.8
$SBank Capacity: ( 80, 100 )
$Shields: 610
$Hitpoints: 275
$Afterburner: YES
+Aburn Max Vel: 0.0, 0.0, 120.0
+Aburn For accel: 0.75
+Aburn Fuel: 400.0
+Aburn Burn Rate: 55.0
+Aburn Rec Rate: 19.0
$Countermeasures: 25
$Name: GTF Myrmidon
+Gun Mounts: 6
+Missile Banks: 3
$Max Velocity: 0.0, 0.0, 75.0
$Rotation time: 4.0, 3.7, 5
$SBank Capacity: ( 20, 20, 40 )
$Shields: 390
$Hitpoints: 290
$Afterburner: YES
+Aburn Max Vel: 0.0, 0.0, 135.0
+Aburn For accel: 0.8
+Aburn Fuel: 320.0
+Aburn Burn Rate: 60.0
+Aburn Rec Rate: 25.0
$Countermeasures: 36
Looking at the Myrmidon compared to the other two staple craft of the GTVA, it's vastly over powered. It's only 5 m/s slower than the Perseus, which was supposed to have some advanced propulsion system, yet it has a stronger hull than even the Herc 2, as well as more countermeasures and a less efficient afterburner - not only that, but uit has more firepower than the supposedly 'Heavy Assault' Herc 2 - if it weren't for the smaller secondary banks, and the lower shielde, the Myrmidon would be far better as a Heavy Assault - I'd say the Harpoon was taken out as an attempt to balance it somewhat...