It'll work no matter what faction you are I think, but yeah any civ faction should be fine regardless of vanilla or modded-in. Reason being that no-matter what faction you are it should switch you to the resistance side on spawn/respawn to give the effect of being a neutral civilian who won't be fired upon while also receiving tasking from the Resistance side.

Let me know if that answers your question.

One thing I noticed was that I was unable to access ammo crates / virtual arsenal as a civ

uhh, I don't think this is anything my script would be doing but just in case you could test the mission file you sent me before it was added in and see if it still occurs.

It would actually be handled by the the C2ISTAR module. Under the auto task OPF, go ahead and set everything as you normally would. Define the opfor faction in the mission, and also define it's enemies. You would then take the exact information and copy paste it under the Auto Task IND section, however you would leave the "Auto task IND faction" as "IND". This would ensure that even when you are technically on the resistance side (JND), you are given the same tasks as you would if you were an opfor in that mission.

If I was going to setup a mission in of this type, this is what I would do. You could have the Opfor side faction be insurgents and set to asymmetric, they will then carry out attacks on blufor while blufor is busy retaliating. You would be fighting for the opfor side but due to the script, you would be changed to the resistance side which will keep you incognito (IND is neutral unless changed in the mission) until you decide to start engaging blufor. Once you engage blufor forces or take a hostile appearance (strap yourself with a bomb, pull a gun out), you will be switched to the opfor (insurgent) side and then be promptly engaged.

Terrible at explanations but hopefully that clarifies it, let me know if it doesn't. If not I could also toss you a quick mission showing kind of how you would start to set it up.

Put this in your description.ext or modify it if it's already in there

respawnOnStart = 0;

If I shout allah akbar, then they do recognise me as hostile however this seems to be proximity based so if I teleport to another part of the map it reverts to friendly.

It's time based to prevent enemies who may not have been in range to hear you say it, engage you as an enemy. The only proximity part is the shouter being revealed to nearby enemies to simulate them being able to "hear" you.

When I strap explosives or pick up a weapon, blufor do not engage.

If you can remove as many mod requirements as possible from the mission and then send it to me I can try to test it myself to see what is going wrong. For example, change factions used to vanilla units and remove any vehicles added via mods.

Yeah I can try to do that, doing stuff with family tonight and prob tomorrow but add me.
Name is the same: SpyderBlack723

Hopefully it's nothing too hard to fix. Just got back into scripting today to work on a few role-tied actions so I might try to maybe fix some of this up if at all possible because it's a mess atm.