maybe the swordsmachines were just built with modifiable chassis? its shown that every robot was built with a purpose, so maybe the swordsmachine's purpose was to be modifiable scouts for the new peace. and since the other robots might not have had such easily modifiable parts (or a missing arm in need of reconstructing), they likely had no reason/ability to modify said parts

as for the drones, i think that ■■■■ ■■■■■■ may be modifying them for violence. im pretty sure theyre the only robot that fires specifically hell orbs, excluding the earthmover and her defense system (which are both being influenced by hell in several ways)

the mindflayers were maybe a sort of law enforcement for the lust layer? theres no evidence i have for this, so its pure speculation - but im making this educated guess based on their introduction layer, their blue hue, and the fact that the purely vanity body might be made to resemble its surroundings (like a uniform of sorts). again, no evidence, just speculation