Did a bit of research.
I believe all major types of gladiators can be done with one sprue.
All the gladiator types are variations on a theme.
Almost all types follow these rules: Large shield you get one greave. Small shield you get two greaves. No shield equals no greaves.
As you can see you would need one sprue with only 4 bodies, 7 heads, 4 kinds of shields, and various arms. (You could probably get away with 6 heads as the Thracian and Hoplomachus helmets are the same.)
If you wanted you could make the "left leg greave" legs seperate with an armored(s) and unarmored torso to aid creation of Samnites, Provocators, Scissors, and maybe Gladiatrixs. Very little reliable detail on the equipment of the scissors but they may have armored torsos. The Provocator could have a seperate torso with breast plate. (Alternatively a glue on breast plate or a breast plate attached to the head would get it done.)
(Provocator breast plate.)
A female torso would allow a Gladiatrix.
There is considerable debate on whether the Gladiatrix fought bare chested or bound up. Stephen Wisdom in "Gladiators 100 BC to AD 200" writes that he thinks they had their breasts covered.
Alternatively one could have a 5th (or 6th) female body (complete) that you would use with the various weapons and full helmets.
Personally, my preferred course of action would be to have no provision for a female gladiator in the first box, and an entire "Gladiators 2 - Female Gladiators" box.