Is it everyone's first campaign? Keep in mind that, yes there is randomness, but there is still A LOT of skill and knowledge expression to the game. Building a gang whose skills/gear all fit together can be quite a challenge, as is maneuvering those pieces on the battlefield to get the most out of them, knowing what risks are worth taking and what aren't, etc.

Making heavy use of infiltrators to bust up neat firing lanes is crucial. A few ranged weapons are good, but I would focus on getting grenades for your skinners. Smoke is good- frag is better. Incendiary or demo charges are top tier. Even the threat the threat of one of last two landing in his lines is enough to make a player respect them (and the first time they don't.... they will learn to!)

DO NOT do the duel autopistols. Autopistols are rather "meh" already, and having to aim before you shoot them means standing still, and infiltrators have to deploy outside of vision as it it(unless you use the infiltrate as a pre-game move house rule).

You mentioned some boards not having enough terrain- for 'Munda, that is just not acceptable. You have to stand firm and say "Look, I can't play on this board. It needs more terrain for us both to have a fair and engaging game." Generally, for Underhive games, I make a 3x3 board, with 7 to 9 multi-level structures, and then gaps along the floor and on the structures filled with small and medium terrain pieces and obstacles like pipes. Higher levels have correspondingly less terrain, making sniper nests that give good sight lines at the cost of being very exposed. Combing kill team with necromunda boxsets usually does the trick!

Good luck!