These are suggestions rather than fully tested and balanced rules
Partisans or guerrilla squads are called as for off-board support. When they show up, the controlling player gets a scenario-determined number of squads of untrained, green or regular quality. Partisans move and hide as snipers but fight as normal infantry. They will not normally have support weapons, just rifles and perhaps an IAVR or two. Partisans communicate with each other at 1 command level separation; with one designated allied liaison at 2 levels of separation; and with other allies as 3 or more levels of separation.
Partisans are always interested in getting more gear, from their own side ("We can't undertake that mission without a machine gun, 2000 rounds of ammo, and a crate of IAVRs. Yes, it is a simple recon mission, but we still won't do it without that") or from the other side if they find a soft target.
The Quick & Dirty combat resolution suggested in the rules is good, but it makes armor more useful at short range than at long range--the opposite of what one would expect. This is because in the Q&D option, you divide the attack dice by the armor dice to yield the number of casualties, and successful long-range attacks will tend to have higher totals than average short range attacks (because they have to beat a higher range die). In other words, long range attacks hit less often than short range, but when they do hit, they do more damage. To correct this, subtract the range die type from the attack total, then divide by armor die.
Example: An IFed squad rolls 4+7+3+10 and hits a PAU squad which has d6 armor and d10 range die. The IFed attack total is 24. In the book's version, this does 24/4 = 6 casualties; in the modified version, this does 24-10 = 14, divide by 6 = 2 casualties.
This rule assumes that you have implemented an Overwatch house rule.
Units which have been trained in professional military technique (ie just about any organized army) may execute Leapfrog Advance. First action: unit goes on overwatch; second action, unit makes a combat move. If during the course of the move the unit spots a previously unseen enemy, or is fired upon, it may use its overwatch action. If the enemy unit is also firing, roll quality dice to determine which fires first. Resolve fire and apply casualties; suppression takes effect only after both units have fired.
Example: an 11 man Islamic Federation squad (quality Regular) makes a leapfrog advance into the line of fire of an 8 man NAC squad (quality Green) on overwatch. The NAC squad wins the QD roll and fires first, inflicting a suppression and two wounds. The IF unit subtracts the firepower of the two casualties and returns fire; then the suppression goes into effect.