Having had a good look at this & taking the WWII conversion attached above into consideration I have some further ideas on this
If we stick with the Necromunda rules model rather than the Mordheim one you would pick a side & within a budget attempt to fill out its force structure. The cost of each figure would include the cost of all its basic gear, with options for intregal special & heavy weapons if appropriate, to which extras could be added if the budget allowed.
However Unlike Necromunda each organisation includes secondary leaders as squad section or its equivalent leaders these would work for their troops as if they where the main leader but not for other troops in their side unless dictated by chain of command if the force had one.
for exampleThe Classic Cadian imperial guard Platoon consists of four infantry squads of nine men including, seven lazgunners & a special weapons team each lead by a sergeant, and a command squad lead by the platoon commander the nine members of which include a communications team & the crew for a heavy weapon as well as another special weapons team, though by default all apart from the Platoon commander are Lazgunners. All are additionally equipped with heavy flack armour
The budget for such a unit should start out as enough to fill out the roster with recruit standard troops, normal quality commander & squad leaders & provide each squad with a special weapon.
Tau fire warriors would operate in teams of six to twelve which would include a leader up to three of which would be deployed lead by an experienced commander who would act as over all force commander & may lead his own team. All would be by default armed with pulse rifles & equipped with standard Tau armour, pulse carbines & the Tau grenades would be at additional cost as would supporting drones & drone teams.
The budget should be sufficient to provide for three Pulse rifle armed teams of twelve including the team leader & counting the overall force commander as one of the team leaders.
To be continued but I hope you see what I am aiming at
Ginger