At the OP, I doubt the Clans would have a loitering or drone anything. It fundamentally takes away from the primacy of the warrior caste. Society drones and loitering munitions? Sure. Clans drones and loitering munitions? No way.
In my headcannon, Clans use Arrow IV two ways.
One is use by dezgra/solahma/freeborn garrison troops in defense of important targets. These warriors are accorded no/little honor to begin with, so it’s no skin off their or their Clan’s nose if they break out the artillery to blunt a trueborn assault against an important military factory, gene repository, etc. I imagine this is where Hueys and Bowmen and Chaparrals are used, but these could also be fixed Arrow IV installations or infantry artillery points with Arrow IV.
Two is use by honorable frontline/trueborn troops against dezgra targets. These targets would typically be Bandit/Dark Caste but would also include Clans/units/etc. marked for Annihilation and the like. There’s no sense in wasting trueborn lives on what are essentially honorless extermination missions. So break out the externally mounted Arrow IV for the trueborn omnifighters, the TAG configurations for the trueborn omnimechs and battle armor, and go to town. Later on, this would also include omnimech V configurations.
None of this explains the Naga, which is a hyper-expensive and wasteful application of omnimech technology in a dedicated role that the Clans disdain. No idea what to chalk the Naga up to other than early Clan writing whose authors had not thought the issues in this thread through.
Hope this helps.