What I know you need to create custom XML files for all the members of your faction and then add them in the Faction XML file.
For example here is basic imperial soldier from Royality.
As you can see there are many different options like a chance for a gunlink or what weapon and apparel they can use. Try to find hediffs for mechanitor stuff in Biotech Defs and add them in the XML file. It should work
For example here is basic imperial soldier from Royality.
Code Select
<PawnKindDef Name="ImperialTrooperBase" Abstract="True" ParentName="ImperialFighterBase">
<combatPower>65</combatPower>
<apparelMoney>5000~8000</apparelMoney>
<weaponTags>
<li>IndustrialGunAdvanced</li>
</weaponTags>
<apparelRequired>
<li>Apparel_FlakJacket</li>
<li>Apparel_FlakVest</li>
<li>Apparel_FlakPants</li>
</apparelRequired>
<initialWillRange>2~4</initialWillRange>
</PawnKindDef>
<PawnKindDef ParentName="ImperialTrooperBase">
<defName>Empire_Fighter_Trooper</defName>
<label>trooper</label>
<apparelColor>(130,130,130)</apparelColor>
<specificApparelRequirements>
<li>
<bodyPartGroup>UpperHead</bodyPartGroup>
<alternateTagChoices>
<li>
<tag>Gunlink</tag>
<chance>0.25</chance>
</li>
</alternateTagChoices>
</li>
</specificApparelRequirements>
<techHediffsTags>
<li>ImplantEmpireCommon</li>
</techHediffsTags>
<skills>
<li>
<skill>Shooting</skill>
<range>4~10</range>
</li>
</skills>
<disallowedTraits>
<li>Brawler</li>
</disallowedTraits>
<initialResistanceRange>15~24</initialResistanceRange>
<useFactionXenotypes>false</useFactionXenotypes>
<xenotypeSet>
<xenotypeChances>
<Neanderthal MayRequire="Ludeon.RimWorld.Biotech">0.03</Neanderthal>
<Hussar MayRequire="Ludeon.RimWorld.Biotech">0.25</Hussar>
<Genie MayRequire="Ludeon.RimWorld.Biotech">0.03</Genie>
</xenotypeChances>
</xenotypeSet>
</PawnKindDef>
As you can see there are many different options like a chance for a gunlink or what weapon and apparel they can use. Try to find hediffs for mechanitor stuff in Biotech Defs and add them in the XML file. It should work