having skimmed the thread, a few thoughts.
the O5P warriors we see in Heir to the Dragon come across as a sort of "poor man's DEST". Tomoe for example is not just a Mechwarrior, but also highly skilled in Infiltration, Espionage, Special Operations, Infantry Tactics, and Melee fighting. basically on par with a real world Special Forces type training. (practically a high tech ninja, with how things are shown in the book)
while i doubt that they receive quite the same degree of cross-training the DEST do (it is doubtful they each would be trained to operate ASF's and battle armor as well as mechs), their military training seems to be a cross between the DEST and ISF skill focuses.
if the O5P was to create a dedicated combat force, it seems liekly to me that they would stick to this sort of 'special operations' emphasis, rather than making a conventional combat force. so i would assume they would deploy in smaller units, with integral Combined Arms in the form of Aerospace fighters, Platoons of Battle Armor, Commando Teams, and whatever transport these require for best effect.
i can see Vehicles being used in fact. while not large MBT's, smaller scouting units like the Pegasus Hover Tanks would make sense, as well as APC's for transporting Battle Armor and Infantry.