Much like endless Inquisitor Necromunda fusion the core roblemof adapting Necromunda is one of emphasis.
Do you want an RPG set in the hive and underhive of Necromunda or just to roleplay a series of skirmishes which happen to be on Necromunda?
I personally would prefer the former. Gangs are the thing that draws people into the setting but they aren`t all that is there just read some kal jericho there are plenty of movers and shakers without house affiliations.
I think freelance scummers (that is underhive dwellers with no house or gang affiliation) are more suitable as a starting point in an RPG as they have no overhanging structure theat predefines them not do they have the headache of trying to translate tabletop archetypes into player paths.
I propose a modular system like regiment creation but on an individual basis. I don`t have myruebbok in frontof me but I`l give it a start.
All characters are created classlessly and have these starting assets.
20 +d10 base statblock
Tech familiarity (+10 on everyday Tech Use tests eg. changing a glowbulb, charging a powercell or rewiring a power outlet)
Weapon training: low tech
100 guilder creds
aptitudes: General. Fellowship
First you determine where players are from in the hive for base additional aptitudes
Spirer + Intelligence, Willpower and Finesse
City dweller + Tougness, Weapon Skill and Tech
Underthiver + Perception, Ballistic Skill and Offence
Then you determine the reason they came to homeless scum
Bounty on head + 50 creds, enemy (pick one)
Adventurer`s Itch + common quality stub auto, knife
and so on.